Abstract: A method of forming an image on a substrate by applying energy, involves a substrate in or on which there are at least two different colour-change agents, i.e. a first colour-change agent capable of giving rise to at least two different colours; and a second colour-change agent capable of giving rise to at least one different colour than achievable with the first colour change agent. A preferred embodiment of the invention is a multi-layer laminate comprising, in order, a layer comprising the first agent, a barrier layer, and a layer comprising the second agent.

Abstract: A method of forming an image on a substrate by applying energy, involves a substrate in or on which there are at least two different colour-change agents, i.e. a first colour-change agent capable of giving rise to at least two different colours; and a second colour-change agent capable of giving rise to at least one different colour than achievable with the first colour change agent. A preferred embodiment of the invention is a multi-layer laminate comprising, in order, a layer comprising the first agent, a barrier layer, and a layer comprising the second agent.

Abstract: A method of forming an image on a substrate by applying energy, involves a substrate in or on which there are at least two different color-change agents, i.e. a first color-change agent capable of giving rise to at least two different colors; and a second color-change agent capable of giving rise to at least one different color than achievable with the first color change agent. A preferred embodiment of the invention is a multi-layer laminate comprising, in order, a layer comprising the first agent, a barrier layer, and a layer comprising the second agent.

Abstract: A method of forming an image on a substrate by applying energy, involves a substrate in or on which there are at least two different colour-change agents, i.e. a first colour-change agent capable of giving rise to at least two different colours; and a second colour-change agent capable of giving rise to at least one different colour than achievable with the first colour change agent. A preferred embodiment of the invention is a multi-layer laminate comprising, in order, a layer comprising the first agent, a barrier layer, and a layer comprising the second agent.

Abstract: A method of forming a coloured substrate, comprising applying to or incorporating within the substrate a diacetylene compound, and exposing the substrate to (i) a first, activating stimulus that converts the diacetylene compound from an unreactive to a reactive form, and (ii) a second stimulus that causes the reactive form of the diacetylene compound to polymerize and form the coloured substrate, wherein the diacetylene compound reverts to its unreactive form on removal of the activating stimulus and is of formula I: Y—C?C—C?C—(CH2)n-T-Q-Z (I) wherein: n=an odd integer; T=CO, CS or a bond; Q=NH, S, O, OCONH, NHCONH, NH—CHE-CONH, NHCOO or NHCSNH wherein E is H or a C1-20 alkyl group; Z=H or a hydrocarbon group containing 1 to 20 carbon atoms; Y=H or any group comprising at least one carbon atom.

Abstract: The invention relates to use of a diacetylene compound as a color former wherein the diacetylene compound has one of general formulae (I) to (V). The invention also includes methods of imparting color to a material including a compound as defined above, which comprises subjecting the material to irradiation.

Abstract: A method for producing a color filter, comprising: applying to a substrate at least one diacetylene capable of undergoing a light-activated color change reaction, and exposing the substrate to light thereby causing the exposed regions of the substrate to change color. The invention also provides devices comprising colored filters such as liquid crystal displays.

Abstract: A laser-markable composition comprises a marking component and an organic compound, wherein the organic compound absorbs laser radiation at 780 to 2000 nm and thereby causes the marking component to change color, and wherein the organic compound has an absorptivity ratio, A r, of at least 1.25, wherein the absorptivity ratio is defined as formula (I): wherein: Ap780-2000 nm is an absorbance peak in the wavelength region of 780 to 2000 nm; and Aave600-700 nm is the average absorbance in the wavelength region of 400 to 700 nm.

Abstract: A compound which undergoes a color change upon irradiation, and which has the general structure: X—C?C—C?C—Y—(CO)n-QZ wherein X is H, alkyl or —Y—(CO)n-QW; each Y is the same or a different divalent alkylene group; Q is O, S or NR; R is H or alkyl; W is H, alkyl or Z; each Z is the same or a different unsaturated alkyl group; and each n is 0 or 1.

Abstract: The invention relates to use of a diacetylene compound as a colour former wherein the diacetylene compound has one of general formulae (I) to (V). The invention also includes methods of imparting colour to a material including a compound as defined above, which comprises subjecting the material to irradiation.

Abstract: A method for producing a colour filter, comprising: applying to a substrate at least one diacetylene capable of undergoing a light-activated colour change reaction, and exposing the substrate to light thereby causing the exposed regions of the substrate to change colour. The invention also provides devices comprising coloured filters such as liquid crystal displays.

Abstract: A compound which undergoes a colour change upon irradiation, and which has the general structure: X—C?C—C?C—Y—(CO)n-QZ wherein X is H, alkyl or —Y—(CO)n-QW; each Y is the same or a different divalent alkylene group; Q is O, S or NR; R is H or alkyl; W is H, alkyl or Z; each Z is the same or a different unsaturated alkyl group; and each n is 0 or 1.

Abstract: A laser-markable composition comprises a marking component and an organic compound, wherein the organic compound absorbs laser radiation at 780 to 2000 nm and thereby causes the marking component to change colour, and wherein the organic compound has an absorptivity ratio, A r, of at least 1.25, wherein the absorptivity ratio is defined as formula (I): wherein: Ap780-2000 nm is an absorbance peak in the wavelength region of 780 to 2000 nm; and Aave600-700 nm is the average absorbance in the wavelength region of 400 to 700 nm.