Abstract: A photosensitive conductive paste that contains (a) a conductive powder in an amount of 70.3 to 85.6 mass % with respect to the total amount of the photosensitive conductive paste; (b) a photosensitive resin composition containing an alkali-soluble polymer, a photosensitive monomer, a photopolymerization initiator, and a solvent; and (c) a glass frit. The mass ratio of the glass frit to the conductive powder is 0.020 to 0.054, and the glass frit has a softening point that is equal to or above the temperature at which sintering of the conductive powder starts.

Abstract: A photosensitive resin composition contains a component (A) and at least one of a component (B) and a component (C). In addition, in the circuit board with metal support including: a metal support; a base insulating layer; a conductive layer formed of a wiring circuit pattern; and a cover insulating layer, at least one of the above-mentioned base insulating layer and cover insulating layer is made of the above-mentioned photosensitive resin composition. (A) a 1,4-dihydropyridine derivative represented by the following general formula (1) where R1 represents an alkyl group having 1 to 3 carbon atoms; and R2 and R3 each represent a hydrogen atom or an alkyl group having 1 or 2 carbon atoms and may be identical to or different from each other; (B) the following (x) and (y): (x) a carboxyl group-containing linear polymer; and (y) an epoxy resin (c) a linear polymer having a carboxyl group and an epoxy group.

Abstract: Disclosed herein is a photosensitive composition comprising a heterocyclic thiol compound or tautomeric form thereof and its method of use on a substrate, which may include a chalcophile substrate.

Abstract: Thick film photoresist compositions are disclosed.

Abstract: Provided is an alkali-developable photosensitive resin composition, the dry coating film of which has a favorable dryness to touch, excellent storage stability and few substances that are harmful to humans. The alkali-developable resin composition comprising (A) a carboxyl group-containing resin, (B) a photopolymerization initiator, (C) a compound with two or more ethylenic unsaturated groups in the molecule, (D) filler and (E) an aromatic petroleum solvent, is characterized in that the naphthalene content of said composition is 300 ppm or less.

Abstract: The invention provides a photosensitive resin composition that can form resists with excellent adhesiveness for conductive layers and that does not easily produce conductive layer discoloration, as well as a photosensitive film employing the composition. A preferred photosensitive film (1) according to the invention comprises a support (11), resin layer (12) and protective film (13), where the resin layer (12) is composed of a photosensitive resin composition comprising a binder polymer, a photopolymerizing compound, a photopolymerization initiator and a benzotriazole derivative represented by the following general formula (1).

Abstract: An alkali development-type solder resist includes (A) a carboxyl group-containing photosensitive resin obtained by reacting (a) a compound having two or more cyclic ether or thioether groups in the molecule with (b) an unsaturated monocarboxylic acid, reacting the product with (c) a polybasic acid anhydride, reacting the resulting resin with (d) a compound having a cyclic ether group and an ethylenic unsaturated group in the molecule, and reacting the product additionally with (c) a polybasic acid anhydride, (B) an oxime ester-based photopolymerization initiator containing a specific oxime ester group, (C) a compound having two or more ethylenic unsaturated groups in the molecule, and (D) a thermosetting component, wherein the dry film obtained by applying the composition has an absorbance of 0.3 to 1.2 per 25 ?m of the film thickness at a wavelength of 350 to 375 nm.

Abstract: A printing plate to form a precise pattern, a method for manufacturing the printing plate, and a method for fabricating an LCD device using the printing plate in which the printing plate includes a substrate having at least one trench and sidewall elements formed at an inner perimeter of the at least one trench.

Abstract: A recording layer including a novel dye for a high density optical recording medium, employing short wavelength laser source with a wavelength not longer than 530 nm for recording high density information and reproduction/playback of the high density information recordings, is provided.

Abstract: A photosensitive resin composition which is excellent in storage stability required for one-part type compositions and in processability required for dry-film formation and gives a cured product suitable for FPC substrates or suspension substrates for hard-disc which each retains essential properties required for solder resists, such as heat resistance, water resistance, and electrical-insulation reliability, and has flexibility and low polluting property. The composition comprises: a compound which has a carbon-carbon double bond and carboxy group and is obtained by allowing a bisphenol type epoxy compound and an unsaturated monocarboxylic acid to react and then allowing a polybasic acid anhydride to undergo addition reaction with part or all of the secondary hydroxy groups of the reaction product; a urethane (meth)acrylate compound having a structure derived from a polycarbonate polyol structure; another polymerizable compound having a carbon-carbon double bond; and a photopolymerization initiator.

Abstract: Printing members that include a plasma polymer layer exhibit enhanced tolerance for high imaging-power densities. The plasma polymer layer may contain or be adjacent to an oleophilic metal such as copper.

Abstract: Disclosed is a presensitized plate composed of a support having thereon an image recording layer which includes: an infrared absorber (A) that is a cyanine dye having at least one fused ring composed of a nitrogen-containing heterocycle in combination with an aromatic ring or a second heterocycle, and having on the aromatic ring or second heterocycle an electron-withdrawing group or a heavy atom-containing group, a radical generator (B), and a radical-polymerizable compound (C), and which is removable with printing ink and/or dampening water. The presensitized of the present invention can be imaged with an infrared light-emitting laser to directly record an image from digital data on a computer or the like and is then subjected to on-machine development without carrying out a development step, which is capable of providing a large number of good impressions with a practical amount of energy.

Abstract: SU-8 photoresist compositions are modified to improve their adhesion properties by adding 1% to 6% of an adhesion promoter selected from the group consisting of glycidoxypropanetrimethoxysilane, mercaptopropyltrimethoxysilane, and aminopropyltrimethoxysilane. SU-8 photoresist compositions are modified to improve their resistance to cracking and film stress by adding 0.5% to 3% of a plasticizer selected from the group consisting of dialkylphthalates, dialkylmalonates, dialkylsebacates, dialkyladipates, and diglycidyl hexahydrophthalates. The improvements can be obtained simultaneously by adding both the adhesion promoter and the plasticizer to SU-8 photoresist compositions.

Abstract: The present invention provides a lithographic printing plate precursor and a lithographic printing method using the lithographic printing plate precursor, which is capable of an image recording by infrared laser scanning and an on-press development and excellent in fine line reproducibility and press life while maintaining good on-press developing properties, the lithographic printing plate precursor comprising: a support; and an image recording layer capable of being removed by a printing ink and/or a fountain solution, in which the image recording layer comprises an infrared absorber and a graft polymer having a specific graft chain.

Abstract: The present invention relates to a paste composition, including a bonding agent charged with a metallic powder, to be used in a prototyping procedure, a procedure for obtaining metallic products from said composition, and a metallic product obtained from said procedure. The composition is characterized by the fact that it includes: a bonding agent comprised of at least one photopolymerizable resin, with a viscosity of less than 4000 mPa.s, measured at 25° C., a photoinitiator, in a concentration greater than 0.2% by mass with respect to the mass of the resin, and a metallic powder in a volumetric concentration greater than 40% with respect to the composition, with said composition having a minimum reactivity on the order of 5 mm3/s per watt of lighting power.

Abstract: A copper clad metal printing plate can be coated with an azide-containing photoresist comprising a polyformal resin together with a modified polyformal resin that has up to 100% of its hydroxyl groups converted to carboxyl groups, an organo azide and a photosensitive dye that absorbs light at the frequency of a patterning laser and converts it to heat energy. This de-crosslinks the resin that has been exposed to the laser light. Preferably the photoresist is flood exposed with ultraviolet light prior to laser exposure. The photoresist becomes soluble in the laser-exposed areas, exposing the underlying copper after development. The printing plates are completed by etching away the copper in the exposed areas, removing the remaining photoresist, thereby providing a patterned copper layer on the printing plate.

Abstract: A method of forming a resist pattern film. A positive type actinic ray decomposing and developing dry film is applied onto a surface of a coating substrate so that the surface of the coating substrate may face to the urethane resin layer of the dry film. Then, the dry film may be heat treated. The non-actinic ray-curable substrate of the dry film, then, is optionally stripped, and is heat treated if it has not already been heat treated. Then, an actinic ray is irradiated through a mask or directly onto the surface of the dry film so as to obtain an intended pattern and is optionally heat treated. The non-actinic ray-curable substrate which was not previously stripped is, then, stripped. Then, the positive type actinic ray-curable urethane resin layer is subjected to a developing treatment. Finally, an unnecessary area of the urethane resin layer to form a resist pattern film is removed.

Abstract: This present invention discloses a photopolymerisable mixture comprising a polymer binder, a radically photopolymerisable component containing at least one photooxidisable group, a polyethylene glycol di(meth)acrylate containing 2 or more ethylene glycol units, a photoreducible dye and a metallocene. This mixture can be used for preparing high-speed light-sensitive recording materials showing a particularly high resolution, especially for small negative types.

Abstract: Disclosed is a support for a lithographic printing plate obtained by subjecting an aluminum plate to a graining treatment and an anodizing treatment, the support comprising at least any one of Mn in a range from 0.1 to 1.5 wt % and Mg in a range from 0.1 to 1.5 wt %; Fe of 0 to 1 wt %; Si of 0 to 0.5 wt %; Cu of 0 to 0.2 wt %; at least one kind of element out of the elements listed in items (a) to (d) below in a range of content affixed thereto, (a) 1 to 100 ppm each of one or more kinds of elements selected from a group consisting of Li, Be, Sc, Mo, Ag, Ge, Ce, Nd, Dy and Au, (b) 0.

Abstract: A composition utilized in and a method for forming an electrode used in field emission type of display devices said composition is a photosensitive copper conductive composition comprising: a mixture of (a) copper powder at least 70 wt % out of 100 wt % copper powders having a particle size in the range of 0.2-3 &mgr;m and (b) an inorganic binder with a softening point in the range of 380-580° C. in an amount of 140 wt % based on 100 wt % copper powders, said mixture being dispersed in an organic vehicle comprising (c) an organic polymer binder, (d) a phototoinitiator, (e) a photohardenable monomer, and an organic solvent; and the photosensitive copper conductive composition being fireable at a temperature in the range of 450-600° C. in a reductive atmosphere.

Abstract: Making a high absorption donor substrate for providing one or more OLED materials to an OLED device by: providing an absorber anti-reflection layer over a transparent support element, the anti-reflection layer having the real portion of its index of refraction greater than 3.0, and a thickness near the first reflectivity minimum at the wavelength of interest; providing a metallic heat-absorbing layer over the anti-reflection layer for absorbing laser light which passes through the transparent support element and the anti-reflection layer; and selecting the transparent support element, the anti-reflection layer, and the metallic heat-absorbing layer to have an average reflectivity of less than 10%, and the micro reflectivity variation due to variations in the thickness of the transparent support element of less than 10% at the wavelength of interest; and providing one or more organic material layers in the absence of a binder material, over the metallic heat-absorbing layer.

Abstract: Disclosed is an etching method of a laminated assembly having a metal layer and a non-thermoplastic polyimide layer bonded together via thermoplastic polyimide, which comprises using an etchant at least containing an alkali metal hydroxide, water and oxyalkylamine, wherein the concentrations of the alkali metal hydroxide (X weight %) and of the water (Y weight %) have relationships represented by coordinate points present within a region (inclusive of boundary lines) defined by the following expressions [1] and [2]: Y=(½)X (provided that 7≦X≦45)  [1] Y=({fraction (5/20)})X+17.5 (provided that 7≦X≦45)  [2] provided that X and Y are defined based on the total weight of the alkali metal hydroxide, water and oxyalkylamine expressed as 100.

Abstract: The optical recording medium has a substrate (1) with a recording layer (2), a reflecting layer (3) and a protecting layer (4) laminated successively on the substrate (1). The reflecting layer (3) is a thin film of an alloy containing 99.7 to 73.0% by weight of Cu as a major component, as well as, 0.2 to 18.0% by weight of Ag and 0.1 to 9.0% by weight of Ti. The reflecting layer has a film thickness of 50 nm to 150 nm. The optical recording medium provided with the reflecting layer (3) shows improved corrosion resistance and also retains high reflectance. The present invention also provides a target for forming the reflecting layer (3).

Abstract: A lithographic printing plate precursor comprising a water-resistant support having provided thereon a light-sensitive layer containing fine titanium oxide grains doped with a metallic ion which absorb a visible ray and a complex composed of an organo-metallic polymer which is formed by a hydrolysis polymerization condensation reaction of a compound represented by formula (I) shown below and an organic polymer which has a group capable of forming a hydrogen bond with the organo-metallic polymer: (R0)nM(Y)x−n  (I) wherein R0 represents a hydrogen atom, a hydrocarbon group or a heterocyclic group; Y represents a reactive group; M represents a metallic atom having from 3 to 6 valences; x represents a valence of the metallic atom M; and n represents 0, 1, 2, 3, 4, 5 or 6, provided that the balance of x−n is not less than 2. A method for the preparation of a lithographic printing plate using the lithographic printing plate precursor is also disclosed.

Abstract: A thinner for rinsing photoresist including 50 to 80 wt. % of n-butyl acetate, propylene glycol alkyl ether, and propylene glycol alkyl ether acetate, is provided. The thinner is neither toxic to humans nor ecologically undesirable and has no unpleasant odor. The waste solutions thereof and associated waste water are easily handed so as to render this thinner environmental friendly. Additionally, the photoresist thinner of the present invention has excellent rinsing ability.

Abstract: A photoimageable, aqueous acid soluble polyimide polymer comprising an anhydride, including a substituted benzophenone nucleus, a diamine reacted with the anhydride to form a photosensitive polymer intermediate, and at least 60 Mole % of solubilizing amine reacted with the photosensitive polymer intermediate to form the photoimageable, aqueous acid soluble polyimide polymer. An emulsion for electrophoretic deposition of a coating of a photoimageable, aqueous acid soluble polyimide polymer comprises a dispersed phase, including the photoimageable aqueous acid soluble polyimide polymer, dissolved in an organic solvent and a dispersion phase including a coalescence promoter and water. The emulsion may be applied, by electrophoretic deposition, to a conductive structure to provide a photoimageable coating on the conductive structure.

Abstract: The present invention relates to a paste composition, including a bonding agent charged with a metallic powder, to be used in a prototyping procedure, a procedure for obtaining metallic products from said composition, and a metallic product obtained from said procedure.

Abstract: A photosensitive thermosetting resin composition has the following essential ingredients: a photopolymerizable prepolymer which is prepared by reacting epoxy resin containing at least two epoxy groups with mono-carboxyl acid [(A2)] containing a vinyl group, and then reacting with saturated or unsaturated polybasic acid anhydride; a thinner, which is selected from photopolymerizable vinyl monomer and/or organic solvent, alone or in combination; a photopolymerizable initiator; an epoxy resin including a soluble crystal state epoxy resin which contains two epoxy groups and is not soluble in the utilized thinner at room temperature but soluble at 60˜80 .degree.C. and/or an epoxy resin which contains at least two epoxy groups and is soluble in the utilized thinner at room temperature; and an inorganic filler.

Abstract: Imagable precursors for masks and for electronic parts comprise a polymeric layer applied to a substrate. The layer comprises at least one polymer having infra-red absorbing groups carried as pendent groups on the polymer backbone. Certain infra-red absorbing groups may also act to insolubilize the polymer in a developer, until it is imagewise exposed to infra-red radiation. Imagewise application of heat, resulting from imagewise exposure of the precursor to infra-red radiation, renders the polymer layer more soluble in the developer than prior to exposure to the infra-red radiation.

Abstract: A composition used as a resist in the manufacture of electronic parts, for example printed circuits, and which is rendered soluble in a developer by pattemwise delivery of heat, comprises a polymer and optionally an infrared absorbing compound. However in contrast to conventional compositions no compound is present which alters the solubility of the polymer in an aqueous developer.

Abstract: A positive acting, composition that can be heat-sensitive is presented, either coated on a lithographic base, or on a printing circuit board base, and comprises a water soluble heat-sensitive resin, a novel adhesion promoter and a radiation absorbing agent—a dye or a pigment. An excellent film forming polymer that comprises acetal units directly pendant from the polymer polyvinyl alcohol backbone may be the only binder resin, when other resins being optional. The solubility of the coated material in the areas exposed to near -IR laser radiation in mild alkaline developers becomes considerably higher, allowing to obtain high resolved patterns of the etch-resistant material on printing circuit boards or lithographic printing plates. The composition can be applied on the substrate from a liquid of laminated as a dry film. Sensitizers may be added to render the composition sensitive to radiation in a non-thermal sense.

Abstract: The present invention relates to use of transition metal complexes in photochromic devices, to the production of optical information storage devices based on a polymeric matrix and on metal oxides with adsorbed transition metal complexes, to the production of photochromic materials constituted by a film of metal oxide with adsorbed two different type of molecular systems, one acting as a charge transfer sensitizer and the second as an electron acceptor.

Abstract: A resist composition comprising: a curable composition mainly comprising (1) at least one of an alkali-soluble acrylic compound and an alkali-soluble methacrylic compound; (2) a fine-particulate crosslinked elastic polymer having a carboxyl group; and (3) an agent for enhancing adhesion with respect to copper.

Abstract: Dry film resists of the invention in general comprise a photoactive component, a highly viscous or solid (at room temperature, ca. 25° C.) crosslinker component, and preferably a flexibilizing agent. Preferred dry film constructions of the invention do not require the use of a protective cover sheet due to the composition's very dry nature.

Abstract: Provided is a photosensitive copper paste permitting the formation of a fine and thick copper pattern having high adhesion to a substrate, and having excellent preservation stability without causing gelation, and a method of forming a copper pattern, a circuit board and a ceramic multilayer substrate using the photosensitive copper paste. The photosensitive copper paste includes a mixture of an organic binder having an acid functional group, a copper powder and a photosensitive organic component. The copper powder has a surface layer having a thickness of at least 0.1 &mgr;m from the surface composed CuO as a main component. The copper powder also has an oxygen content of about 0.8% to 5% by weight.

Abstract: A composition used as a resist in the manufacture of electronic parts, for example printed circuits, and which is rendered soluble in a developer by patternwise delivery of heat, comprises a polymer of general formula (I), wherein R1 represents a hydrogen atom or alkyl group, R2 represents a hydrogen atom or alkyl group, R3 represents a hydrogen atom or alkyl group, and R4 represents hydroxyalkyl group, and wherein the ratio n/m is in the range 10/1 to 1/10.

Abstract: The invention provides improved resist compositions and lithographic methods using the resist compositions of the invention. The resist compositions of the invention are acid-catalyzed resists which are characterized by the presence of an SiO-containing polymer. The invention also encompasses methods of forming patterned material layers (especially conductive, semiconductive, or magnetic material structures) using the combination of the SiO-containing resist and a halogen compound-containing pattern transfer etchant where the halogen is Cl, Br or I.

Abstract: A photoimageable, aqueous acid soluble polyimide polymer comprising an anhydride, including a substituted benzophenone nucleus, a diamine reacted with the anhydride to form a photosensitive polymer intermediate, and at least 60 Mole % of solubilizing amine reacted with the photosensitive polymer intermediate to form the photoimageable, aqueous acid soluble polyimide polymer. An emulsion for electrophoretic deposition of a coating of a photoimageable, aqueous acid soluble polyimide polymer comprises a dispersed phase, including the photoimageable aqueous acid soluble polyimide polymer, dissolved in an organic solvent and a dispersion phase including a coalescence promoter and water. The emulsion may be applied, by electrophoretic deposition, to a conductive structure to provide a photoimageable coating on the conductive structure.

Abstract: A photoimageable, aqueous acid soluble polyimide polymer comprising an anhydride, including a substituted benzophenone nucleus, a diamine reacted with the anhydride to form a photosensitive polymer intermediate, and at least 60 Mole % of solubilizing amine reacted with the photosensitive polymer intermediate to form the photoimageable, aqueous acid soluble polyimide polymer. An emulsion for electrophoretic deposition of a coating of a photoimageable, aqueous acid soluble polyimide polymer comprises a dispersed phase, including the photoimageable aqueous acid soluble polyimide polymer, dissolved in an organic solvent and a dispersion phase including a coalescence promoter and water. The emulsion may be applied, by electrophoretic deposition, to a conductive structure to provide a photoimageable coating on the conductive structure.

Abstract: An optical information recording medium comprising a light transmitting substrate, a light absorptive layer containing at least one light absorbing substance formed on the substrate and a light reflective layer made of a metal film formed on the light absorptive layer, wherein an optical parameter represented by &rgr;=nabsdabs/&lgr; wherein nabs is the real part of the complex refractive index of the light absorptive layer, dabs is the average thickness of the light absorptive layer and &lgr; is the wavelength of a reading laser beam, is 0.6<&rgr;<1.6.

Abstract: Multicurved copper films having fine-line elements suitable for radome applications can be improved by cutting the elements with reproducible precision to close tolerance (typically line widths of 3-10±0.25 mil) using an etchant comprising a concentrated saline solution of CuCl2.

Abstract: Radiation sensitive compositions, processes for using the compositions, and articles of manufacture comprising the compositions. The compositions of the invention are use to form flexible coatings having a dielectric constant of 3 or less. The compositions comprise a resin binder and a polybutadiene that comprises one or more internal epoxide groups. In preferred aspect of the invention, the compositions of the invention further comprise a crosslinking agent capable of solvating the remaining constituents of the composition. The coatings are used for the manufacture of electronic and other devices.

Abstract: A positive acting, heat-sensitive composition is presented, either coated on a lithographic base, or on a printing circuit board base, and comprises a water insoluble heat-sensitive resin, a novel adhesion promoter and a radiation absorbing agent—a dye or a pigment. An excellent film forming polymer that comprises acetal units directly pendant from the polymer polyvinyl alcohol backbone may be the only binder resin, when other resins being optional. The solubility of the coated material in the areas exposed to near-IR laser radiation in mild alkaline developers becomes considerably higher, allowing to obtain high resolved patterns of the etch-resistant material on printing circuit boards or lithographic printing plates. The composition can be applied on the substrate from a liquid or laminated as a dry film.

Abstract: To provide a photosensitive resin composition and a photosensitive element using the resin composition with excellent sensitivity and adhesion as well as high resolution and plating resistance. A photosensitive resin composition, comprises (A) a polymer carrying carboxyl groups, (B) a compound carrying at least one ethylene-based unsaturated group in the molecule, and (C) a photopolymerization initiator, characterized by the fact that component (B) contains at least 60 weight % of methacrylate (B1) carrying at least one ethylene-based unsaturated group with respect to the total amount of component (B), that the amount of component (C) is in the range of 0.01-20 weight units with respect to 100 weight units of component (A) and component (B), and that component (C) contains 2-5 weight units of lophine dimer (C1) and 0.1-2.0 weight units of triphenylphosphine (C2) with respect to 100 weight units of component (A) and component (B), as well as a photosensitive element using the resin composition.

Abstract: A flexible, flame-retardant, aqueous processable, photoimageable resin composition for forming a permanent, protective coating film for printed circuitry and a multilayer photoimageable element containing a layer of the photoimageable resin composition in combination with a low tack photoimageable resin sublayer and a temporary support film are disclosed. The photoimageable resin composition has excellent aqueous developability and provides a cured coating film having good flexibility, adhesion, solvent resistance, surface hardness, thermal resistance, electrical insulating properties and flame retardancy.

Abstract: A waterborne photoimageable composition or photoresist comprises a latex binder polymer based on a waterborne dispersion of a photopolymerizable urethane acrylate oligomer having sufficient carboxylic acid functionality to render it develop able in alkaline aqueous solution and a photo initiator chemical system and other components to produce an aqueous coatable and alkali develop able photoresist composition.

Abstract: The invention provides a negative-acting photoimageable composition comprising A) between about 30 and about 80 wt % based on total weight of A) plus B) of a binder polymer having acid functionality sufficient to render said photoimageable composition developable in alkaline aqueous solution, B) between about 20 and about 70 wt % based on total weight of A) plus B) of an addition-polymerizeable, non-gaseous &agr;,&bgr;-ethylenically unsaturated compound(s) capable of forming a high polymer by free-radical initiated chain-propagating addition polymerization, at least about 50 mole percent of the &agr;,&bgr;-ethylenically unsaturated moieties of B) being methacrylic moieties, and C) between about 0.1 and about 20 wt % based on total weigh of A) plus B) of a photoinitiator chemical system. Photopolymerizable component B comprises, at between about 1 and about 70 wt. % relative to total of A) plus B) a biuret urethane oligomer having &agr;,&bgr;-ethylenic unsaturation.

Abstract: A positive acting, photoimageable composition having, a photoacid generator capable of generating an acid upon exposure to actinic radiation, an organic acid anhydride polymer, an epoxy, a nitrogen-containing curing catalyst, and an optional phenol-containing monomer or polymer. A photographic element has this composition coated and dried on a substrate. A positive acting image is produced by imagewise exposing the element to actinic radiation, optionally postbaking and development with a liquid developer.

Abstract: Photochemical acid progenitors in combination with dihydroperimidine squarylium dyes have been found to be particularly effective at generating acid upon irradiation with new-infrared radiation. It has been found that dihydroperimidine squarylium dyes that are particularly useful in this invention have an oxidation potential greater than about 0.5 V relative to SCE as measured in dichloromethane.