350 s SR

XR 4 035527 ' United State 1 4,035,527 . w Deeg .. 15 July 12, 1977

(54) METHOD OF PROVIDING A PHOTOTROPIC LAYER ON A CARRIER OTHER PUBLICATIONS Mader; K., “Photochromic Spectacle ' Manufac (75) Inventor: Emil W. Deeg, Woodstock, Conn. turing International, Jan. 1973, pp. 34-38. Perveyev; A. F. et al., "AgCl-CuCl Photochromic 73) Assignee: American Optical Corporation, Coatings," Soviet Journal of Optical Technology, Feb. Southbridge, Mass. 1972, pp. 117-118. 21 Primary Examiner-John K. Corbin Appl. No.: 527,987 Assistant Examiner-Rolf Hille 22) Filed: Nov. 29, 1974 Attorney, Agent, or Firm-H. R. Berkenstock, Jr.; William C. Nealon (51) Int. Cl.’...... G02B 5123; B05D 5/06 57 ABSTRACT (52) U.S. C...... 427/169; 4271164; A laminated optical or ophthalmic element is produced 350/160 P; 106/DIG. 6 comprised of an amorphous and/or crystalline material 58) Field of Search ...... 350/60 P; 156/106; possessing phototropic or photochromic properties as a 106/DIG. 6; 4271167, 166, 162, 168, 169 result of applying a thin layer over at least one surface References Cited thereof, which layer includes a combination of cations (56) and anions including or copper bromide and/or U.S. PATENT DOCUMENTS chloride. 3,208,860 97.965 Armistead et al...... 350,160 PX 3,875,321 4/1975 Glieneroth et al...... 350/60 PX 4 Claims, No Drawings

s 4,035,527 1 2 by weight of silver halides and sensitizers), U.S. Pat. METHOD OF PROVIDING A PHOTOTROPIC No. 3,449, 103 (similar to 3,208,860), U.S. Pat. No. LAYER ON A CARRIER 3,548,060 (borate or alumina-alkaline-earth borate type with silver halides plus copper sensitizer), BACKGROUND U.S. Pat. No. 3,594,198 (borate, silica-borates with It is considered desirable to provide glassy, amor potassium and silver halides), U.S. Pat. No. 3,615,761 phous and/or crystalline material which possesses pho (phosphate, barium aluminum phosphate, thallous ha totropic or photochromic properties. Particular utility lide and copper as the photosensitive system), U.S. Pat. for such a product is found in . As is well No. 3,617,316 (comparable to 3,548,060 above but known, there are two primary markets for sunglasses; 10 with small amounts of zinc oxide, lead oxide, and 1-5% namely, Rx or prescription and plano. The plano is by weight of silica), U.S. Pat. No. 3,630,765 (tantalum usually a less expensive product which may be used by aluminum borosilicate with 10-30% by weight of ce those persons not requiring vision correction. The Rix sium oxide and a silver halide and copper photosensi lens is used by those requiring correction. The present tive system). invention has utility in either the Rx prescription or 15 In addition, U.S. Pat. Nos. 3,540,793 and 3,653,863 plano market. It is also usable with image display and are of interest. These patents disclose polarizing photo storage systems, photochromic windows, and the like. chromic utilizing elongated parallel oriented silver halide crystals as the active agent. THE PUBLISHED PATENTS Various of the above patented systems require criti The following patents are not directly related to oph 20 cal chemistry or batch parameters such as control of thalmic or optical applications but are believed perti reduceable metal content, absence of trace elements, nent published patents: U.S. Pat. No. 3,607,320 is di lack of absorbing ions, or like layers rected to a phototropic glass or ceramic article. U.S. as a protective coating, control of pore size, require Pat. No. 2,770,922 relates to radiation colorable chro ment of batch processing rather than continuous pro mium glass usable as a dosimeter for monitoring high 25 cessing, exposure to x-rays or gamma-rays or the like to energy radiation. U.S. Pat. No. 3,541,330 is directed to nucleate or otherwise modify included materials, heat a photochromic glass-image storage arrangement. U.S. treatment to precipitate submicroscopic crystals such Pat. No. 3,428,396 is directed to a photochromic glass as silver halide crystals, diffusion of chemicals into base image display and storage system. U.S. Pat. No. glass, thickness control for the articles or substrates, 3,406,085 is concerned with a photochromic window 30 control of refractive indexes and various combinations utilizing a photochromic glass. U.S. Pat. No. 3,508,810 of the foregoing. is concerned with an organic photochromic system and In known glass compositional systems including a describes a sandwich consisting of a pair of transparent halide as a constituent, increased of pressing glass sheets sealed together by means of a resin con tools, for example, when making blanks, can be ex taining a dissolved photochromic material, i.e., a spiro 35 pected. Special alloys have to be used or a reduced tool pyran. U.S. Pat. No. 3,436,144 is concerned with pho lifetime must be accepted. Slight variations of halide tochromic materials and devices and in particular and sensitizer contents in certain glasses can result in metal cyanimide and organic dye indicators. U.S. Pat. significant changes in the response or recovery time No. 3,407,145 is concerned with photochromic means from a clear to an activated transmission state. (This and methods and in particular trimethyl-1,3, 3-indo 40 can be most undesirable in a sunglass). Furnace atmo line, 2-spiro - 2' 2H pyrodino - 2,3-(b) pyrans. sphere and glass chemistry and subsequent heat treat The following patents relate to photochromic materi ment have to be continuously monitored because of the als and are pertinent to this invention: U.S. Pat. No. criticality of halide content in the final product. 3,255,026 (a reduced silicate glass with CeOa - MnO Volatilization of halides in the fabrication of certain as the photosensitive agent), U.S. Pat. No. 3,269,847 45 of the above products (also borates) requires personnel (strongly reduced soda-silicate glass and soda-lime-sili protection to an increased degree and additional facili cate glass with Eropium and having a wavelength of ties for ventilating furnace areas and filtering furnace activating radiation at 575 nanometers), U.S. Pat. No. exhaust gases to prevent ecological contamination. 3,272,646 (a using an aromatic diamino Many of the above patented systems require special tetraacetic acid as a photosensitive agent), U.S. Pat. 50 ized substrates or base materials containing relatively No. 3,278,319 (a strongly reduced soda-silicate glass precise quantities of specified chemicals, such as ha and soda-lime-silicate glass with up to 25% by weight of lides, for example. The manufacture of such glasses is cerium), U.S. Pat. No. 3,615,771 (cadmium-silica very difficult on a large scale and may require such with either silver or copper oxide sensi unusual process treatments as bubbling chlorine gas or tizer), U.S. Pat. No. 3,664,725 (a glass body including 55 the like through melts plus subsequent treatment as, for trivalent erbium and using trivalent ytterbium and/or example, heat treatment, irradiation or the like. neodymium as a sensitizer), U.S. Pat. No. 3,197,296 The present invention has among its objects elimina (alumina-boro-silicate with some lead, alkali and fluo tion of many of the foregoing difficulties and provision ride with a sensitizer agent of such as silver chloride, of a composite system or product exhibiting reversible bromide or iodide and copper as a sensitizer), U.S. Pat. 60 optical density change. It is a further object of the No. 3,208,860 (a base glass of a silicate, boro-silicate, invention to provide an arrangement for deposition of a or aluminaboro-silicate with silver chloride, bromide or phototropic or photochromic layer on substantially any iodide and copper as a sensitizer), U.S. Pat. No. ophthalmic or optical glass or plastic lens. It is a further 3,306,833 (comparable to 3,208,860 above), U.S. Pat. object to provide a phototropic or photochromic layer No. 3,325,299 (a silver-free silicate glass but compara 65 on a glass or plastic optical or ophthalmic lens. ble to U.S. Pat. No. 3,208,860 above), U.S. Pat. No. Yet another object is to provide amorphous and/or 3,328, 182 (comparable to U.S. Pat. No. 3,208,860), crystalline material possessing phototropic or photo U.S. Pat. No. 3,419,370 (aluminaboro-silicate plus 5% chromic properties such that after excitation with ultra 3 4,035,527 4 violet or shortwave visible light there is a change in the then added with additional mixing. The batch was dried light transmission characteristics of such a material. and repulverized. The batch was then made into pellets Briefly, according to a preferred embodiment of the on a Clifton-hydraulic press at a gauge pressure of invention there is provided means to produce a photo 3,800 pounds per square inch. The resulting pellets tropic or photochromic silver halide activated coating 5 were sintered in a conventional electric box-type labo for glass or plastic optical or ophthalmic . These ratory furnace at 1600 for 1 hour. Each sintered pellet coatings or thin films can be fabricated, for example, by weighed approximately 3 grams. Eight pellets were multiple electron beam vacuum deposition. These films made from the foregoing batch. Additional batches can include a considerably higher concentration of were made to manufacture more pellets. such as silver halide crystals than specificed in pub- 10 The following table indicates a preferred batch mix lished patent systems of the type above mentioned with ture by weight of constituents: related advantages being accomplished. DETAILED DESCRIPTION OF THE INVENTION Grams According to one aspect of this invention there is 15 EastP Flint 54.327.68 taught the chemical deposition of a thin photochromic Al2Os 4.36 or phototropic layer on any type of optical or ophthal- E. 33 mic substrate. For example, the substrate may be a AgNO .84 conventional CR-39, or diallyl glycol carbonate, lens. NaC 4.08 Other useable ophthalmic quality include 20 polymethylmethacrylates or such as "Plexiglas”, “Lexan", "Lucite". While the preferred EXAMPLE II glassidentical substrate to composition is ophthalmic A, other crown optical glass, or ophthalmic similar or preparedAn additional and from batch it 24of theadditional same oxide pellets analysis were prewas glasses such as compositions B through L. may be used. 25 pared at a pressure of 5,200 pounds per square inch on EXAMPLE I the Clifton press. . . . a s Pellets prepared according to either of the foregoing The following is an exemplary batch analysis: examples are suited for vacuum deposition on either glass or plastic substrates. For example, pellets of the % 30 above type are placed in a water-cooled crucible in a vacuum chamber. For example, CR-39 lenses to be SiO, (as potters flint) 77.6 used as the substrate are placed inside a water-cooled SiO 1.97 crucible in a vacuum chamber about 559 millimeters 2 (as NaSiO) above a crucible in which a pellet prepared according NaO/ 2 3 35 to the above examples is placed and the chamber is AlOs (as calcined alumina) 2.8 pumped down to a high vacuum in a conventional man KF (as KHF) 1.34 ner, i.e., 6 X 10 Torr. An electron beam is directed AgOBOs (as(as BOs)AgNO) 4.039.81 onto a sample until it is partially melted and evapo NaO (as NaCl) 108 rated. The film thickness is monitored optically by 0 interferometry. More details of this process are found, For purposes of this invention, an operative glass layer to example: in cepending application Ser. No. includes 5-60 mol percent Ag" and 8-85 mol percent 10,270, filed Sept. 30, 1974, by Leei Chang et al, the of material selected from the group consisting of Cl, disclosure thereof being included herein by reference. Br, and mixtures thereof. According to broader aspects of the present inven

A* B C D E F G H J K L SiO, 68.0 62.40 68.0 63.35 62.00 62.00 61.07 46.83 38.9 43.59 34.10 65.28 NaO 8.5 9.02 8.2 9.35 8.72 8.72 8.37 5.65 6.74 2.59 1.90 7.27 KO 9.2 740 8.9 8.45 9.83 9.83 8.32 6.70 - 1.50 7.60 500 9.88 CaO. 8.5 8.5 -- - - 4.0 6.00 -- - - ZnO 3.5 - 0.84 3.0 7.75 7.90 7.90 74 2.00 - - 40 22 AlOs 1.8 2.91 1.9 2.50 2.50 2.50 4.34 100 - 1.30 1.80 2.5 AsOs 0.2 - 0.5 0.25 0.25 0.25 ------SbOs 0.2 0.76 0.5 0.25 0.25 0.25 0.82 00 0.30 0.50 0.50 - TiO, 0.4 100 . . 0.5 0.75 1.20 120 - 3.72 4.28 1.52 - 4.25 0.75 MgO -- 4.12 - 3.25 3.25 3.25 4.22 ------w BO - .00 - i.10 l. 10 l. 10 1.00 5.00 2.00 - - - LaOs - m - 3.00 - al- - " - - --- CodO - - 3.00 -- - - - M- - BaO - - - 3.00 - 2.50 18.80 - - - ZrO, - - - - - 2.50 6.00 1.50 - 0.90 - PbO - - - re- - - 16, 19 41.40 50.15 - FeO ------2.09 "(A above is the preferred glass substrate composition) All the solid ingredients (that is, all except the silver nitrate and the sodium chloride) were mixed and pull tion, the coating material has an analysis in the follow verized in mortar with a pestle. The silver nitrate was 65 ing range: dissolved in distilled water. The solution of distilled water and silver nitrate was added to the pulverized Wt, 2. batch and mixed thoroughly. the sodium chloride was SiO, 82-66 4,035,527 5 6 -continued This coating can also be applied to the CR-39 lens by Wt, % dipping in the solution at room temperature for 10 NaO 14-3 AlOs 0-4 seconds and thereafter being exposed to a halogen, e.g. KF (a flux) 0-5. . . a mixture of chlorine-and-bromine-vapor-containing BOs 2-i4 air atmosphere during the hardening process. AgCl, AgBr, or mixtures thereof 4-20 The hardening process takes place while the dip, or spin, coated lens is placed in a laboratory furnace at a One of the desirable aspects of forming optical and temperature of 93° C. for a period of 30 minutes. After ophthalmic photochromic or phototropic layers ac O such treatment the coated lens is removed from the cording to this invention is the flexibility which is pro furnace and allowed to cool freely at room tempera vided to certain aspects of ophthalmic business. It can ture. Exposure to the halogen-containing atmosphere simplify warehousing and inventory problems since one takes place in complete darkness. It is also advisable to can coat clear, as well as colored or tinted, glass or perform the dipping in a darkroom environment using plastic lenses with phototropic materials thus eliminat 15 red light illumination only as standard practice in pho ing or reducing requirements for multiple inventories tographic laboratories. of various glasses. The invention further opens totally The liquid coating can also be applied by dropping new concepts in the photochromic lens art. One can approximately 1 cubic centimeter of the liquid onto the now supply such exotic lenses as purple, green, or other surface of a lens spinning at 2000 rpm. The rotation of fashion shades which will exhibit photochromicity. 20 the lens is stopped after 5 seconds, the lens is removed Glasses can be considered to be super-cooled liquids from the holder and is exposed to the atmosphere de quenched to a solid state at a high enough rate to pre scribed. vent crystalization. Impurities such as silver halides can It is possible to replace the mixture ethanol/butanol? act as nucleating agents for localized crystal formation. HNO/tetra-ethyl-ortho-silicate by solutions known in Large numbers of smaller crystals normally cause opac 25 commerce as "Phosphorosilicafilm' and “Borosilica ification of the glass. It is for this reason, among others, film'. that production of lens blanks according to procedures The aqueous silver and copper nitrate solutions are of various of the published patents discussed above are added to the quantities described above. These solu limited to silver halide concentrations of quite low tions are manufactured by Emulsitone Company, order concentration, i.e., concentrations of less than 30 Whippany, N.J. 0.1 volume percent, for example. Practice of the pre Whereas the main constituent of the coating pre sent invention allows much higher concentrations of pared from the solution mentioned first is silica, use of silver halide, avoidance of opacification, greater com the other solutions permits formation of glass coatings patibility with a wide variety of optical and ophthalmic consisting essentially of boro-silicates and phospho-sili substrates without undue concern over indexes of re 35 cates as carriers of the photochromic silver halide par fraction trace impurities in the substrate, differential ticles. thermal expansion, and the like. : , , In addition to the foregoing, more conventional oph In the above description we have considered organic thalmic and optical amorphous and/or crystalline plas and inorganic materials from which one obtains a glass tics and glasses, other substrates may be used. For coating by vacuum deposition. Dipping in a solution 40 example, a glass or plastic lens including a polarizing with subsequent treatment is possible if necessary. optical layer therein, as, for example, disclosed in U.S. Other known techniques may be utilized, for example, Pat. No. 3,674,587, may be used. including flame apraying of silver halide-containing In conclusion, it may be observed that glasses con droplets of the sintered pellets described above on a taining silver halide presently are believed to be impor cold lens. 45 tant as photochromic or phototropic substances. The It should be understood that small amounts of various carrier of phototropism in these glasses is a separate types of sensitizing agents can be added to the coating phase. The present invention provides a means compositions according to this invention. For example, whereby this phase is deposited onto a substrate and such sensitizing agents as copper in the form of a cop still shows phototropic or photochromic behavior. This per chloride or copper bromide or mixtures thereof 50 photochromic or phototropic behavior can be opti may be added. mized in a thin layer as compared to a plastic or con In the foregoing description we have discussed the ventional glass optical or ophthalmic lens. According fabrication of sintered pellets which by vacuum deposi to this thin layer technique, the more unstable silver tions are used to form thin layers on selected optical halide phase is limited to a comparatively thin layer. In and ophthalmic substrates. In addition it is possible to 55 addition, formation of an amorphous substance, which fabricate such photochromic or phototropic layers according to this invention is the thin layer containing from solutions of soluble metal oxide compounds in the silver halide crystals, by vacuum deposition allows cluding such as silver nitrate. For example, such as quenching more rapidly than any other glass-forming CR-39 plastic ophthalmic lens can be coated with the technique, known to us at this time, thus avoiding opac following mixture: 60 ification by crystal growth during formation of the amorphous substance. EXAMPLE III Other inorganic glasses and optical or ophthalmic 13 volume parts of ethanol quality organic materials or plastics, other than those 4 volume parts of butanol elsewhere listed, having the mechanical compatibility 1 volume part of 40% HNO. 65 necessary with the thin coating of the invention are 2 volume parts of tetra-ethyl-ortho-silicate equally usable. l volume part of 0.1 molar aqueous solution of copper According to the foregoing, we have taught the fabri nitrate and silver nitrate. cation of elements or products comprised of an amor 4,035,527 7 8 phous or crystalline material possessing phototropic uniform and substantially free of undue opacification. properties and comprised of a substrate and a thin Photochromic or phototropic color centers, which are coating. After excitation with ultraviolet or shortwave the cause of the reversible coloration, are substantially visible light, there is a reversible increase in resistance uniformally distributed through the thin layer. Prefer in light absorption. ably the glass layer is less than 20 um thick. To recapitulate: we have provided an amorphous Having thus described the invention in detail and and/or crystalline material, according to this invention, with sufficient particularity as to enable those skilled in comprised of an optical or ophthalmic quality of or the art to practice it, what we desire to protect by let ganic or inorganic substrate. Over at least one surface ters patent is set forth in the following claims. of the substrate there is formed a thin phototropic or O I claim: photochromic glass layer which is capable of a revers 1. That method of rendering at least one major sur ible excitation upon exposure to ultraviolet or short face of an optical or ophthalmic organic or inorganic wave visible light. The layer is comprised of a glass lens phototropic comprised of the steps: matrix which includes 5-60 mol percent of Agt and a. preparing a clean lens surface to be treated; 8-85 mol percent of a halide selected from the group 15 b. preparing a liquid temporary-carrier of a stable comprised of Cl, Br and mixtures thereof. In addi solution of a mixture of silicon containing metal tion, the layer may include a minor, but effective organic compound and a metal organic compound amount, of a sensitizer. The most common and the containing boron and phosphorous with nitric acid preferred sensitizer is the metal ion Cu. and copper nitrate and silver nitrate, said mixture The preferred glass for the matrix is selected from the 20 being pyrolyzable to form a glassy matrix compris group consisting of silicates, boro-silicates, and phos ing SiO, POs, and BO and mixtures thereof for phosilicates. Practically all usable glasses are listed in the phototropic material to be placed on the lens; the table under the designations A through L under c. exposing the said clean lens surface to said tempo Example I above. rary-carrier and phototropic-layer-forming mate As noted above, the preferred concept according to 25 this invention is an ophthalmic quality sunglass lens rial under conditions capable of depositing a thin, having at least one major surface thereof covered by a hard, scratch-resistant glass layer over said lens phototropic layer. The method of preparing a lens is surface, said layer having substantially uniformly comprised of the following steps: to assure intimate distributed therewith color centers which, when association between the glass matrix carrying the pho 30 subjected to ultraviolet or shortwave visible light totropic or photochromic ion system and the optical, or exhibit reversible absorption thereof. ophthalmic lens, to be coated, the lens must first be 2. The method of claim 1 wherein said temporary cleaned. The necessary clean lens surface can be ac carrier is the solution of: complished in any conventional manner. For example, 13 volume parts of ethanol first washing in an ultrasonic detergent bath, perhaps 35 4 volume parts of butanol followed by an ethanol bath and a Freon bath. 1 volume part of 40% HNO Thephototropic material is prepared in a temporary 2 volume parts of tetra-ethyl-ortho-silicate carrier. For example, it may be placed in a sealed melt 1 volume part of 0.1 molar aqueous solution of cop able pellet or in a solution. The pellet, or solution, is per nitrate and silver nitrate. then operatively associated with a clean lens surface. 40 3. The method of claim 1 including the step of expos This, for example, operative assocation can be in a ing said lens coated with said temporary-carrier and vacuum furnace, a solution, by spin casting, all of the ingredients for forming a phototropic layer to a halogen systems being above described in more detail. The to form said phototropic layer. : exposure of the lens to the halide system is under con 4. The method of claim 1 wherein said layer is hard ditions and for a time period sufficient to form a thin, 45 ened in a furnace having a halogen atmosphere at an hard, scratch-resistant glass layer over the surface of elevated temperature. the lens to be coated. The layer must be substantially sk ck xk sk sk

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