# US 2014/0154808 A1 · Monitoring system based on etching of metals > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2014/0154808 A1 - Document ID: US20140154808A1 - Status: Published application - Kind: A1 - Application number: 13/692,939 - Filed: 2012-12-03 - Published: 2014-06-05 - Earliest claimed: 2012-12-03 - Inventors: Gordhanbhai N. Patel - Web page: https://patentgrep.com/patent/US20140154808A1 ## CPC - A61L 2/07: Steam - A61L 2/206: Ethylene oxide - A61L 2/28: Devices for testing the effectiveness or completeness of sterilisation or disinfection, e.g. indicators which change colour - C09D 11/037: characterised by the pigment - C09D 11/322: Pigment inks - C12Q 1/22: Testing for sterility conditions - G01K 3/04: in respect of time - G01N 31/229: {for investigating time/temperature history} - G01N 33/02: Food - G01N 33/52: Use of compounds or compositions for colorimetric, spectrophotometric or fluorometric investigation, e.g. use of reagent paper {and including single- and multilayer analytical elements (immunological elements G01N33/54386; involving labelled immunochemicals G01N33/58; for haemoglobin or occult blood G01N33/72)} - A61L 2202/14: Means for controlling sterilisation processes, data processing, presentation and storage means, e.g. sensors, controllers, programs - Y10T 156/10: Methods of surface bonding and/or assembly therefor - Y10T 436/206664: Ozone or peroxide - A61L: METHODS OR APPARATUS FOR STERILISING MATERIALS OR OBJECTS IN GENERAL; DISINFECTION, STERILISATION OR DEODORISATION OF AIR; CHEMICAL ASPECTS OF BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES; MATERIALS FOR BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES (preservation of bodies or disinfecting characterised by the agents employed A01N; preserving, e.g. sterilising, food or foodstuffs A23; preparations for medical, dental or toiletry purposes A61K) - C09D: COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR (cosmetics A61K; processes for applying liquids or other fluent materials to surfaces, in general, B05D; staining wood B27K5/02; glazes or vitreous enamels C03C; natural resins, French polish, drying-oils, driers, turpentine, per se, C09F; polishing compositions other than French polish, ski waxes C09G; adhesives or use of materials as adhesives C09J; materials for sealing or packing joints or covers C09K3/10; materials for stopping leaks C09K3/12; processes for the electrolytic or electrophoretic production of coatings C25D) - C12Q: MEASURING OR TESTING PROCESSES INVOLVING ENZYMES, NUCLEIC ACIDS OR MICROORGANISMS (immunoassay G01N33/53); COMPOSITIONS OR TEST PAPERS THEREFOR; PROCESSES OF PREPARING SUCH COMPOSITIONS; CONDITION-RESPONSIVE CONTROL IN MICROBIOLOGICAL OR ENZYMOLOGICAL PROCESSES - G01K: MEASURING TEMPERATURE; MEASURING QUANTITY OF HEAT; THERMALLY-SENSITIVE ELEMENTS NOT OTHERWISE PROVIDED FOR (radiation pyrometry G01J5/00) - G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q) - Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION ## Abstract Compositions, devices and processes related to etching of a very thin layer or fine particles of a metal are disclosed for monitoring a variety of parameters, such as time, temperature, time-temperature, thawing, freezing, microwave, humidity, ionizing radiation, sterilization and chemicals. These devices have capabilities of producing a long and sharp induction period of an irreversible visual change. The devices are composed of an indicator comprising a very thin layer of a metal and an activator, e.g., a reactant, such as water, water vapor, an acid, a base, oxidizing agent or their precursors, which is capable of reacting with the said indicator. Ink formulations composed of a metal powder and a proper activator can be used for monitoring several sterilization processes, such as sterilization with steam. When water is used as an activator, a thin layer of metals, such as that of aluminum can be used as steam sterilization or humidity indicator. ## Claims ### Claim 1 An indicating system comprising: an indicating layer comprising a zero-valent metal or metal alloy and metal oxide; and an activator layer comprising an activator or a precursor of said activator wherein said activator or said precursor of said activator renders said indicator layer transparent upon reaction, and the system is capable of providing an induction period. ### Claim at position 2 2-3. (canceled) ### Claim at position 3 6-10. (canceled) ### Claim at position 4 12-27. (canceled) ### Claim at position 5 29-40. (canceled) ### Claim at position 6 42-47. (canceled) ### Claim at position 7 49-54. (canceled) ### Claim at position 8 56-65. (canceled) ### Claim at position 9 67-68. (canceled) ### Claim at position 10 70-91. (canceled) ### Claim at position 11 93-127. (canceled) ### Claim at position 12 129-130. (canceled) ### Claim 131 (depends on 1) The indicating system of claim 1 wherein the zero-valent metal or metal alloy of the indicator layer comprises a material that has at least one property selected from the group consisting of conductive, reflective, highly opaque, self-binding and impermeable and further has a property of being able to be etched or destroyed when contacted with the activator or said precursor of said activator. ### Claim 132 (depends on 1) The indicating system of claim 1 wherein the reaction product after the indicator layer is contacted with the activator or said precursor of said activator has at least one property selected from the group consisting of being non-conductive, non-reflective and permeable. ### Claim 133 (depends on 1) The indicating system of claim 1 wherein the metal or metal alloy is selected from the group consisting of alkali metals, alkaline earth metals, transition metals, post transition metals, lanthanides and actinides metals and their alloys. ### Claim 134 (depends on 133) The indicating system of claim 133 wherein the metal is selected from the group consisting of aluminum, tin, zinc, copper, manganese, magnesium, nickel, cobalt, iron, sodium, potassium, lithium, calcium, gallium, cesium, germanium, indium, silver and their alloys. ### Claim 135 (depends on 134) The indicating system of claim 134 wherein the metal is selected from the group consisting of aluminum, copper, zinc, tin and their alloy. ### Claim 136 (depends on 133) The indicating system of claim 133 wherein the metal, metal alloy or metal oxide reacts with water, acids, bases, chemicals, chemical or biological agents and salts. ### Claim 137 (depends on 133) The indicating system of claim 133 wherein the metal or metal alloy is that of aluminum. ### Claim 138 (depends on 1) The indicating system of claim 1 wherein the activator layer comprises a composition that reacts with the indicator layer to cause an irreversible change in the indicator layer. ### Claim 139 (depends on 1) The indicating system of claim 1 wherein the activator comprises at least one agent selected from the group consisting of water, oxygen, organic acids, inorganic acids, bases, salts, biological agents and chelates. ### Claim 140 (depends on 1) The indicating system of claim 1 which comprises said precursor of the activator. ### Claim 141 (depends on 1) The indicating system of claim 1 wherein the activator is an inorganic acid. ### Claim 142 (depends on 141) The indicating system of claim 141 wherein the inorganic acid is selected from the group consisting of phosphoric acid, phosphorous acid, hydrochloric acid, nitric acid, sulfuric acid, sulfonic acid, and a mixture thereof. ### Claim 143 (depends on 1) The indicating system of claim 1 wherein the activator is a hydroxide, alkoxide, or aryloxide of a metal or a cation of nitrogen. ### Claim 144 (depends on 1) The indicating system of claim 1 wherein the activator is a salt of a weak acid and a strong base, a strong acid and a weak base, a strong acid and a strong base, or a weak acid and a weak base or a combination thereof. ### Claim 145 (depends on 1) The indicating system of claim 1 wherein the activator is selected from the group consisting of a halide, oxide, nitrate, nitrite, phosphate, phosphite, phosphonate, silicate, sulfate, bisulfate, sulfite, sulfide, bisulfide, sulfonate, cyanate, cyanide, thiocyanate, acetylacetonate, carboxylate, percarboxylate, carbonate or bicarbonate anion of a mono, di and trivalent cation of a metal or cation of nitrogen, sulfur, phosphorous, halogens and mixture thereof. ### Claim 146 (depends on 1) The indicating system of claim 1 wherein the activator is selected from the group consisting of ammonium bromide, ammonium thiocyanate, calcium chloride, copper chloride, copper ammonia complex, lithium acetylacetonate, lithium chloride, lithium formate, phosphorous, phosphorous pentoxide, potassium acetate, potassium benzoate, potassium bromide, potassium chloride, potassium ferrocyanide, potassium ferricyanide, potassium formate, sodium acetate, sodium bicarbonate, sodium bromide, sodium carbonate, sodium cyanate, sodium diethyldithiocarbamate, sodium iodide, sodium metasilicate, sodium nitrate, sodium sulfite, sodium tetrafluoroborate, sodium tetraborate, sodium thiocyanate, sodium thiosulfate, tetraethylammonium bromide, zinc chloride and a mixture thereof. ### Claim 147 (depends on 1) The indicating system of claim 1 wherein the activator is a chelate or complex of a metal cation. ### Claim 148 (depends on 1) The indicating system of claim 1 wherein the activator is an amine or ammonia complex of a metal cation. ### Claim 149 (depends on 1) The indicating system of claim 1 wherein the activator is an amine or ammonia complex of copper chloride or nickel chloride. ### Claim 150 (depends on 1) The indicating system of claim 1 wherein the activator layer is in close contact with or in proximity of the indicator layer. ### Claim 151 (depends on 1) The indicating system of claim 1 wherein the activator is oxygen, chemical vapor or water. ### Claim 152 (depends on 1) The indicating system of claim 1 wherein the activator is humidity, steam, or microwave radiation, and further wherein the activator or the precursor of the activator reacts directly with the indicator layer. ### Claim 153 (depends on 1) The indicating system of claim 1, wherein the activator comprises at least one agent selected from the group consisting of humidity, steam, ethylene oxide, formaldehyde, ozone, peracetic acid, hydrogen peroxide, a chemical agent and a biological agent. ### Claim 154 (depends on 1) The indicating system of claim 1 wherein the indicator layer is deposited on a substrate. ### Claim 155 (depends on 154) The indicating system of claim 154 wherein the substrate is a plastic film wherein said indicator layer is a continuous metal layer thickness of less than about 10,000 Angstroms. ### Claim 156 (depends on 155) The indicating system of claim 155 wherein the continuous metal layer has a thickness of less than about 1,000 Angstroms. ### Claim 157 (depends on 154) The indicating system of claim 154 wherein the metal or metal alloy) is particulate with a thickness of less than about 10 microns. ### Claim 158 (depends on 155) The indicating system of claim 155 wherein the indicator layer is bound to said substrate to form a metallized plastic film. ### Claim 159 (depends on 1) The indicating system of claim 1 which further comprises: a binder which binds the activator layer and indicator layer. ### Claim 160 (depends on 1) The indicating system of claim 1 wherein the indicator layer is affixed to a substrate. ### Claim 161 (depends on 160) The indicating system of claim 160 wherein the substrate is a plastic film. ### Claim 162 (depends on 1) The indicating system of claim 1 which further comprises a binder for the activator. ### Claim 163 (depends on 162) The indicating system of claim 162 wherein the activator layer is affixed to a substrate. ### Claim 164 (depends on 163) The indicating system of claim 163 wherein the substrate comprises a pressure sensitive adhesive. ### Claim 165 (depends on 1) The indicating system of claim 1 which further comprises: a) an indicator tape affixed to a first substrate wherein said indicator tape comprises said indicator layer; and b) an activator tape affixed to a second substrate wherein said activator tape comprises said activator or the precursor of the activator dispersed in a matrix layer wherein said indicator tape and said activator tape are bonded together with at least one adhesive. ### Claim 166 (depends on 165) The indicating system of claim 165 which has at least one message which appears—in color, or as a word or symbol on at least on one side of the indicator layer. ### Claim 167 (depends on 166) The indicating system of claim 166 wherein the message or its portion is on both sides of the indicator layer. ### Claim 168 (depends on 167) The indicating system of claim 167 which contains at least two messages wherein a first message of said two messages does not start to appear at a same time as a second message of said two messages. ### Claim 169 (depends on 168) The indicating system of claim 168 wherein a first appearing message indicates a status or quality of an item when the indicating system is applied on or before a treatment of the item and a second appearing message alone or in combination with the first indicates status or quality of the item after the treatment. ### Claim 170 (depends on 169) The indicating system of claim 169 wherein the first appearing message indicates un-doneness, freshness, usability, acceptability, untreated, unexposed, or non-sterile, non-usability, not-acceptability and the second appearing message alone or in combination with the first indicates doneness, expiration, spoilage, not usability unacceptability, treated, and exposed, sterile, usability and acceptability. ### Claim 171 (depends on 160) The indicating system of claim 160 which further comprises a system wherein an additional one or more layers are added to the system, wherein the additional layers are selected from the group consisting of a binder layer, a permeable to activator layer, a wedge shaped permeable to activator layer, a barrier to activator layer, a reactive, destroyable or degradable barrier layer, an expiration indicating layer, a tamper indicating layer, an activation indicating layer, a message or image creating layer, separating layer, removable layer, a disappearing layer, activatable layer, a microencapsulated layer and a thermally printable layer. ### Claim 172 (depends on 1) The indicating system of claim 1 which can monitor a material or a process. ### Claim 173 (depends on 172) The indicating system of claim 172 wherein the material is, a chemical, a chemical agent or a biological agent. ### Claim 174 (depends on 172) The indicating system of claim 172 wherein the process is time, temperature, time-temperature, freeze, thaw, heating, cooling, humidity, doneness of food, microwave, pressure, ionizing radiation and sterilization including sterilization with steam, ethylene oxide, a peroxide, plasmas of a peroxide, formaldehyde, dry heat or ionizing radiation. ### Claim 175 (depends on 174) The indicating system of claim 174 wherein the process of time-temperature is used for monitoring shelf life, usability, freshness, of perishables comprising one or more of fresh, refrigerated, or frozen, vegetables, fruits, meats, fish, poultry, dairy products, bakery products, juices, pre-cooked foods, soft and alcoholic beverages, and the non-food item is a pharmaceutical, vaccine, biological compound, cosmetics, reactive chemical compound, biochemical product, battery, x-ray film or photographic film. ### Claim 176 (depends on 175) The indicating system of claim 175 wherein the biological compound is sera, blood, or blood plasma. ### Claim 177 (depends on 165) The indicating system of claim 165 which further comprises an adhesive layer to attach the indicating system to an item to be monitored. ### Claim 178 (depends on 165) The indicating system of claim 165 further comprising at least one electronic chip or component connected to the conductive path. ### Claim 179 (depends on 165) The indicating system of claim 165 wherein said activator tape is applied on at least a portion of at least one conductive path of an electronic device composed of at least one electronic chip wherein the activator or the precursor of the activator has capability of destroying the conductive path. ### Claim 180 (depends on 179) The indicating system of claim 179 wherein the electronic device is a radio frequency identification device or an electronic article surveillance device. ### Claim 181 (depends on 1) The indicating system of claim 1 which has at least one message which appears as in color, word or symbol on at least on one side of the indicator layer. ### Claim 182 (depends on 181) The indicating system of claim 181 wherein the message or its portion is on both sides of the indicator layer. ### Claim 183 (depends on 182) The indicating system of claim 182 which contains at least two messages wherein a first message of said two messages does not start to appear at a same time as a second message of said two messages. ### Claim 184 (depends on 183) The indicating system of claim 183 wherein a first message indicates a status or quality of an item when the indicating system is applied on or before a treatment of the item and a second message alone or in combination with the first indicates status or quality of the item after the treatment. ### Claim 185 (depends on 184) The indicating system of claim 184 wherein the first message indicates un-doneness, freshness, usability, acceptability, untreated, unexposed, or non-sterile, non-usability, not-acceptability and the second message alone or in combination with the first indicates doneness, expiration, spoilage, not usability unacceptability, treated, and exposed, sterile, usability and acceptability. ### Claim 186 (depends on 1) The indicating system of claim 1 which further comprises a) a binder, and b) at least one substrate; wherein the metal, metal alloy or metal oxide is in the form of particles. ### Claim 187 (depends on 1) The indicating system of claim 1 wherein the indicator layer further comprises indicating ink, paint, gel, or plastisol. ### Claim 188 (depends on 187) The indicating system of claim 187 wherein the indicating system has a liquid vehicle. ### Claim 189 (depends on 1) The indicating system of claim 1 wherein the precursor for the activator is an acid, base, salt, organo-metallic compound or a chemical agent or a biological agent. ### Claim 190 (depends on 189) The indicating system of claim 189 wherein the precursor for the activator is phosphorous pentoxide. ### Claim 191 (depends on 140) The indicating system of claim 140 which comprises a pre-precursor for said precursor for the activator. ### Claim 192 (depends on 191) The indicating system of claim 191 wherein the pre-precursor is white or yellow phosphorus. ### Claim 193 (depends on 140) The indicating system of claim 140 wherein the precursor for the activator is a monomeric or polymeric halo, halide, halonium, sulfonium or phosphonium compound. ### Claim 194 (depends on 1) The indicating system of claim 1 which further comprises a system wherein an additional one or more layers are added to the system, wherein the additional layers are selected from the group consisting of a binder layer, a permeable to activator layer, a wedge shaped permeable to activator layer, a barrier to activator layer, a reactive, destroyable or degradable barrier layer, an expiration indicating layer, a tamper indicating layer, an activation indicating layer, a message or image creating layer, separating layer, removable layer, a disappearing layer, activatable layer, a microencapsulated layer and a thermally printable layer. ### Claim 195 (depends on 165) The indicating system of claim 165 wherein the indicator tape and the activator tape comprise a sealing tape, said indicating system having a two tape dispenser for the sealing tape, wherein two tapes are dispensed simultaneously when applying the sealing tape on a container wherein one tape of said two tapes is said indicator tape and a second tape of said two tapes is said activator tape. ### Claim 196 (depends on 1) The indicating system of claim 1 which further comprises a substrate with a printed message. ### Claim 197 (depends on 1) The indicating system of claim 1 wherein a time required for a change in the indicator layer or an activation energy of the system is varied or adjusted by changing one or more of the parameters selected from the group consisting of: thickness of the activator layer, thickness of the indicator layer, thickness of the permeable layer, concentration of the activator, concentration of the precursor, concentration of an additive in the activator, concentration of an additive in the permeable layer, nature of a solvent, surfactant and a catalyst, nature of the activator layer, nature of the indicator layer, nature of the permeable layer, nature of the additive and nature of a reaction accelerator and retarder. ### Claim 198 (depends on 1) The indicating system of claim 1 which is a high accuracy optical waveguide monitor, an electronic circuit or an electronic article surveillance. ### Claim 199 (depends on 1) The indicating system of claim 1 which is a safety sticker, self-timing retail sticker, biological industrial process monitor, self-expiring sticker to prevent re-use, security ID label, visitors badge, self-expiring parking tag, package and shipping label, wrist band, time indicating ticket for trains, buses, spot events, theaters, self-expiring pass for tours, emergency rooms, hospitals, museums, and other locations, race track pass, security label for screened luggage, purse, bag at airports to indicate that such items have been inspected, or a self-expiring visitor label issued at unmanned but video controlled entrances for visitors. ### Claim 200 (depends on 1) The indicating system of claim 1 which is a toy, gimmick, message, pattern, design, gift card, or greeting card. ### Claim 201 (depends on 1) The indicating system of claim 1 which is a part of an radio frequency identification device, electronic article surveillance or printed circuit board. ### Claim 202 (depends on 1) The indicating system of claim 1 which is a device to monitor radon and alpha particles. ### Claim 203 (depends on 154) The indicating system of claim 154 which comprises a second indicator layer on the other side of the substrate. ### Claim 204 (depends on 1) The indicating system of claim 1 wherein the activator layer is on a substrate. ### Claim 205 (depends on 204) The indicating system of claim 204 wherein there is a second activator layer on the other side of the substrate. ### Claim 206 (depends on 1) The indicating system of claim 1 which is an indicating device for different classes of sterilization. ### Claim 207 (depends on 1) The indicating system of claim 1 wherein the induction period is measured by a delay in a visual indication of the destruction of the metal, metal alloy or metal oxide. ### Claim 208 An indicating system comprising: a zero-valent opaque metal or metal alloy indicator layer, an oxide layer wherein said metal is selected from the group consisting of aluminum, zinc and copper; and a layer of an activator or a precursor of said activator wherein said activator or said precursor renders said indicator layer? transparent upon reaction with said activator. ### Claim 209 A process to monitor the status of medical products, food, or biological waste which comprises placing an indicating system comprising: a zero-valent metal or metal alloy indicator layer; a metal oxide layer; a layer of an activator or a precursor of said activator on a packaging of said medical products, food, or biological waste; and the system is capable of providing an induction period. ### Claim 210 A process to monitor a limited time consumer use for items that have been opened or in use and should be used within a certain period comprising: placing an indicating system comprising a zero-valent opaque metal, metal alloy indicator layer, or a metal oxide layer and a layer of an activator or a precursor of said activator, near an item to be monitored, wherein the item is selected from the group consisting of drinks, food items, health, personal and family care products wherein when said indicator becomes transparent said certain period has expired; and the system is capable of providing an induction period. ### Claim 211 A process to make an indicating system comprising a zero-valent metal, metal alloy indicator layer, a metal oxide layer and a layer of an activator or a precursor of said activator comprising: laminating an activator tape comprising said layer of said activator or said precursor of said activator on said metal or metal alloy indicator layer; and the system is capable of providing an induction period. ### Claim 212 A process to make an indicating system comprising a zero-valent metal, metal alloy indicator layer, or a metal oxide layer and a layer of an activator or a precursor of said activator comprising: coating said layer of activator or precursor of said activator on said metal, metal alloy or metal oxide indicator layer wherein said metal, metal alloy or metal oxide indicator is on a support; coating onto said support at least one additional layer selected from the group consisting of a permeable layer, a wedge shaped permeable layer, a barrier layer, a reactive, destroyable or degradable barrier layer, an expiration indicating layer, a tamper indicating layer, an activation indicating layer, a message or image creating layer, separating layer, removable layer, a disappearing layer, activatable layer, a microencapsulated layer and a thermally printable layer; and the system is capable of providing an induction period. ### Claim 213 A process to determine the concentration of an agent comprising: monitoring a change in conductivity, or opacity of an indicator layer of an indicating system comprising a zero-valent metal or metal alloy indicator layer, a metal oxide layer and a layer of an activator or a precursor of said activator; and the system is capable of providing an induction period. ### Claim 214 A process to monitor a change in a material or a process comprising: measuring a change in the material or the process with an indicating system comprising a zero-valent metal or metal alloy indicator layer, a metal oxide layer and a layer of an activator or a precursor of said activator; and the system is capable of providing an induction period. ### Claim 215 (depends on 214) The process of claim 214 wherein the material is a perishable, a medical product, a chemical, a chemical agent or a biological agent. ### Claim 216 (depends on 214) The process of claim 214 wherein the process is a change in time, temperature, time-temperature, freeze, thaw, heating, cooling, humidity, doneness of food, microwave, pressure, radiation and sterilization including sterilization with steam, ethylene oxide, a peroxide, plasmas of a peroxide, formaldehyde, dry heat and ionizing radiation. ### Claim 217 (depends on 216) The process of claim 216 wherein the change of time-temperature is monitored to indicate shelf life of perishables comprising one or more of fresh, refrigerated, or frozen, vegetables, fruits, meats, fish, poultry, dairy products, bakery products, juices, pre-cooked foods, soft and alcoholic beverages, pharmaceutical, vaccine, biological sample, cosmetics, reactive chemical compound, biochemical product, battery, x-ray film or photographic film. ### Claim 218 (depends on 217) The process of claim 217 wherein the biological sample is sera, blood, or blood plasma. ### Claim 219 (depends on 211) The process of claim 211 wherein the indicating system further comprises an adhesive layer to attach the indicating system to an item to be monitored. ### Claim 220 (depends on 214) The process of claim 214, a patterned layer of a barrier material and the layer of said activator or said precursor of said activator, wherein when activated, the barrier material protects certain areas selected by the pattern on the indicator layer, allowing the remaining metal or metal alloy layer to create a message or at least one conductive path for an electronic device, or a metal or metal alloy pattern. ### Claim 221 (depends on 220) The process of claim 220 wherein the indicating system further comprises at least one electronic chip or component connected to the conductive path. ### Claim 222 (depends on 214) The process to monitor a change in a material or a process of claim 214 wherein the indicating system wherein said induction period is measured by a delay in a visual indication of the change in the material or process. ### Claim 223 (depends on 222) The process of claim 222 wherein the induction period in the indicating system is created by the destruction of the destructible metal, metal alloy or a metal oxide layer. ### Claim 224 (depends on 222) The process of claim 222 wherein the indicating system comprises a destructible metal or metal alloy indicator layer, a destructible barrier layer, and the layer of the activator or the precursor of said activator and the induction period is created by the destruction of the destructible barrier layer. ### Claim 225 (depends on 222) The process of claim 222 wherein the indicating system comprises a destructible metal or metal alloy indicator layer, a destructible barrier layer, and the layer of the activator or the precursor of said activator and the induction period is created by the destruction of the destructible metal or metal alloy indicator layer and the destructible barrier layer. ### Claim 226 (depends on 222) The process of claim 222 wherein the indicating system comprises a destructible metal or metal alloy indicator layer, a permeable layer, and the layer of the activator or the precursor of said activator and the induction period is created by the destruction of the destructible metal or metal alloy layer. ### Claim 227 (depends on 222) The process of claim 222 wherein the indicating system comprises a destructible metal or metal alloy indicator layer, a destructible barrier layer, a permeable layer, the layer of the activator or the precursor of said activator and the induction period is created by the destruction of the destructible metal or metal alloy indicator layer, and the destructible barrier layer. ### Claim 228 (depends on 224) The process of claim 224 wherein the destructible barrier layer is a metal oxide layer. ### Claim 229 (depends on 225) The process of claim 225 wherein the destructible barrier layer is a metal oxide. ### Claim 230 (depends on 227) The process of claim 227 wherein the destructible barrier layer is a metal oxide. ### Claim 231 (depends on 222) The process of claim 222 which is a process of monitoring time, temperature, time-temperature, freeze, thaw, heating, cooling, humidity, doneness of food, microwave, pressure, radiation and sterilization including sterilization with steam, ethylene oxide, a peroxide, plasmas of a peroxide, formaldehyde, dry heat and ionizing radiation. ### Claim 232 (depends on 223) The process of claim 223 which is a process of monitoring time, temperature, time-temperature, freeze, thaw, heating, cooling, humidity, doneness of food, microwave, pressure, radiation and sterilization including sterilization with steam, ethylene oxide, a peroxide, plasmas of a peroxide, formaldehyde, dry heat and ionizing radiation. ### Claim 233 (depends on 224) The process of claim 224 which is a process of monitoring time, temperature, time-temperature, freeze, thaw, heating, cooling, humidity, doneness of food, microwave, pressure, radiation and sterilization including sterilization with steam, ethylene oxide, a peroxide, plasmas of a peroxide, formaldehyde, dry heat and ionizing radiation. ### Claim 234 (depends on 225) The process of claim 225 which is a process of monitoring time, temperature, time-temperature, freeze, thaw, heating, cooling, humidity, doneness of food, microwave, pressure, radiation and sterilization including sterilization with steam, ethylene oxide, a peroxide, plasmas of a peroxide, formaldehyde, dry heat and ionizing radiation. ### Claim 235 (depends on 226) The process of claim 226 which is a process of monitoring time, temperature, time-temperature, freeze, thaw, heating, cooling, humidity, doneness of food, microwave, pressure, radiation and sterilization including sterilization with steam, ethylene oxide, a peroxide, plasmas of a peroxide, formaldehyde, dry heat and ionizing radiation. ### Claim 236 (depends on 227) The process of claim 227 which is a process of monitoring time, temperature, time-temperature, freeze, thaw, heating, cooling, humidity, doneness of food, microwave, pressure, radiation and sterilization including sterilization with steam, ethylene oxide, a peroxide, plasmas of a peroxide, formaldehyde, dry heat and ionizing radiation. ### Claim 237 (depends on 228) The process of claim 228 which is a process of monitoring time, temperature, time-temperature, freeze, thaw, heating, cooling, humidity, doneness of food, microwave, pressure, radiation and sterilization including sterilization with steam, ethylene oxide, a peroxide, plasmas of a peroxide, formaldehyde, dry heat and ionizing radiation. ### Claim 238 (depends on 229) The process of claim 229 which is a process of monitoring time, temperature, time-temperature, freeze, thaw, heating, cooling, humidity, doneness of food, microwave, pressure, radiation and sterilization including sterilization with steam, ethylene oxide, a peroxide, plasmas of a peroxide, formaldehyde, dry heat and ionizing radiation. ### Claim 239 (depends on 230) The process of claim 230 which is a process of monitoring time, temperature, time-temperature, freeze, thaw, heating, cooling, humidity, doneness of food, microwave, pressure, radiation and sterilization including sterilization with steam, ethylene oxide, a peroxide, plasmas of a peroxide, formaldehyde, dry heat and ionizing radiation. ### Claim 240 (depends on 1) The indicating device of claim 1 wherein the induction period is higher than 5% of the total period of the device. ### Claim 241 (depends on 240) The indicating system of claim 240 where in the induction period is higher than 50% of the total period of the device. ### Claim 242 (depends on 240) The indicating system of claim 240 where in the induction period is higher than 80% of the total period of the device. ### Claim 243 (depends on 240) The indicating system of claim 240 where in the induction period is higher than 95% of the total period of the device. ### Claim 244 (depends on 1) The indicating system of claim 1 where in the induction period is due to change in opaqueness or conductivity. ### Claim 245 (depends on 166) The device of claim 166 wherein the symbol is a barcode. ### Claim 246 (depends on 245) The device of claim 245 wherein a part of the barcode is printed above and the balance is printed below the opaque metal or metal alloy layer. ### Claim 247 (depends on 1) The device of claim 1 wherein the thickness of the metal oxide layer is between 5-1000 Angstroms. ### Claim 248 (depends on 247) The device of claim 247 wherein the thickness of the metal oxide layer is between 10-50 Angstroms. ### Claim 249 The indicating system comprising: At least one substrate; an indicator layer comprising a zero-valent opaque metal or metal alloy; a layer of metal oxide; a layer of activator or a precursor of said activator wherein said activator or said precursor of said activator in a polymeric matrix/binder renders said indicator layer transparent upon reaction; wherein the system is capable of providing an induction period. ### Claim 250 (depends on 249) The indicating system of claim 249 wherein the indicator layer comprises a material that has at least one property selected from the group consisting of conductive, reflective, highly opaque, self-binding and impermeable and further has a property of being able to be etched or destroyed when contacted with the activator or said precursor of said activator. ### Claim 251 (depends on 249) The indicating system of claim 249 wherein the reaction product after the indicator layer is contacted with the activator or said precursor of said activator has at least one property selected from the group consisting of being non-conductive, non-reflective and permeable. ### Claim 252 (depends on 249) The indicating system of claim 249 wherein the metal or metal alloy is selected from the group consisting of alkali metals, alkaline earth metals, transition metals, post transition metals, lanthanides and actinides metals and their alloys. ### Claim 253 (depends on 252) The indicating system of claim 252 wherein the metal is selected from the group consisting of aluminum, tin, zinc, copper, manganese, magnesium, nickel, cobalt, iron, sodium, potassium, lithium, calcium, gallium, cesium, germanium, indium, silver and their alloys. ### Claim 254 (depends on 253) The indicating system of claim 253 wherein the metal is selected from the group consisting of aluminum, copper, zinc, tin and their alloy. ### Claim 255 (depends on 249) The indicating system of claim 249 wherein the metal, metal alloy or metal oxide reacts with water, acids, bases, chemicals, chemical or biological agents and salts. ### Claim 256 (depends on 252) The indicating system of claim 252 wherein the metal or metal alloy is that of aluminum. ### Claim 257 (depends on 249) The indicating system of claim 249 wherein the activator layer comprises a composition that reacts with the indicator layer to cause an irreversible change in the indicator layer. ### Claim 258 (depends on 249) The indicating system of claim 249 wherein the activator comprises at least one agent selected from the group consisting of water, oxygen, organic acids, inorganic acids, bases, salts, biological agents and chelates. ### Claim 259 (depends on 249) The indicating system of claim 249 which comprises said precursor of the activator. ### Claim 260 (depends on 249) The indicating system of claim 249 wherein the activator is an inorganic acid. ### Claim 261 (depends on 260) The indicating system of claim 260 wherein the inorganic acid is selected from the group consisting of phosphoric acid, phosphorous acid, hydrochloric acid, nitric acid, sulfuric acid, sulfonic acid, and a mixture thereof. ### Claim 262 (depends on 249) The indicating system of claim 249 wherein the activator is a hydroxide, alkoxide, or aryloxide of a metal or a cation of nitrogen. ### Claim 263 (depends on 249) The indicating system of claim 249 wherein the activator is a salt of a weak acid and a strong base, a strong acid and a weak base, a strong acid and a strong base, or a weak acid and a weak base or a combination thereof. ### Claim 264 (depends on 249) The indicating system of claim 249 wherein the activator is selected from the group consisting of a halide, oxide, nitrate, nitrite, phosphate, phosphite, phosphonate, silicate, sulfate, bisulfate, sulfite, sulfide, bisulfide, sulfonate, cyanate, cyanide, thiocyanate, acetylacetonate, carboxylate, percarboxylate, carbonate or bicarbonate anion of a mono, di and trivalent cation of a metal or cation of nitrogen, sulfur, phosphorous, halogens and mixture thereof. ### Claim 265 (depends on 249) The indicating system of claim 249 wherein the activator is selected from the group consisting of ammonium bromide, ammonium thiocyanate, calcium chloride, copper chloride, copper ammonia complex, lithium acetylacetonate, lithium chloride, lithium formate, phosphorous, phosphorous pentoxide, potassium acetate, potassium benzoate, potassium bromide, potassium chloride, potassium ferrocyanide, potassium ferricyanide, potassium formate, sodium acetate, sodium bicarbonate, sodium bromide, sodium carbonate, sodium cyanate, sodium diethyldithiocarbamate, sodium iodide, sodium metasilicate, sodium nitrate, sodium sulfite, sodium tetrafluoroborate, sodium tetraborate, sodium thiocyanate, sodium thiosulfate, tetraethylammonium bromide, zinc chloride and a mixture thereof. ### Claim 266 (depends on 249) The indicating system of claim 249 wherein the activator is a chelate or complex of a metal cation. ### Claim 267 (depends on 249) The indicating system of claim 249 wherein the activator is an amine or ammonia complex of a metal cation. ### Claim 268 (depends on 249) The indicating system of claim 249 wherein the activator is an amine or ammonia complex of copper chloride or nickel chloride. ### Claim 269 (depends on 249) The indicating system of claim 249 wherein the activator layer is in close contact with or in proximity of the indicator layer. ### Claim 270 (depends on 249) The indicating system of claim 249 wherein the activator is oxygen, chemical vapor or water. ### Claim 271 (depends on 249) The indicating system of claim 249 wherein the activator is humidity, steam, or microwave radiation, and further wherein the activator or the precursor of the activator reacts directly with the indicator layer. ### Claim 272 (depends on 249) The indicating system of claim 249, wherein the activator comprises at least one agent selected from the group consisting of humidity, steam, ethylene oxide, formaldehyde, ozone, peracetic acid, hydrogen peroxide, a chemical agent and a biological agent. ### Claim 273 (depends on 249) The indicating system of claim 249? wherein the indicator layer is deposited on the substrate. ### Claim 274 (depends on 273) The indicating system of claim 273 wherein the substrate is a plastic film wherein said indicator layer is a continuous metal layer thickness of less than about 10,000 Angstroms. ### Claim 275 (depends on 274) The indicating system of claim 274 wherein the continuous metal layer has a thickness of less than about 1,000 Angstroms. ### Claim 276 (depends on 273) The indicating system of claim 273 wherein the metal or metal alloy is particulate with a thickness of less than about 10 microns. ### Claim 277 (depends on 274) The indicating system of claim 274 wherein the indicator layer is bound to said substrate to form a metallized plastic film. ### Claim 278 (depends on 249) The indicating system of claim 249 which further comprises: a binder which binds the activator layer and indicator layer. ### Claim 279 (depends on 249) The indicating system of claim 249 wherein the indicator layer is affixed to a substrate. ### Claim 280 (depends on 279) The indicating system of claim 279 wherein the substrate is a plastic film. ### Claim 281 (depends on 249) The indicating system of claim 249 which further comprises a binder for the activator. ### Claim 282 (depends on 281) The indicating system of claim 281 wherein the activator layer is affixed to the substrate. ### Claim 283 (depends on 281) The indicating system of claim 281 wherein the substrate comprises a pressure sensitive adhesive. ### Claim 284 A process of creating induction period in an indicating system which comprises placing an indicating layer on a substrate; exposing the indicating layer to an activator; and allowing the activator to destroy the indicating layer; wherein the indicating layer is not destroyed immediately, thereby creating an induction period. ### Claim 285 A process of creating at least two induction periods in an indicating system which comprises preparing an indicating system having at least two indicating layers, each indicating layer responding differently to the same activator, wherein the indicating layers are destroyed at different rates.