Photosensitive material and laser marking method

A photosensitive material wherein an emulsion layer having a thickness S is formed on a surface of a base layer, while a laser beam having an almost circular beam spot shape is irradiated onto the emulsion layer to form a dot pattern, and the dot pattern is arrayed by M number in a column and N number in a row and a character or a mark whose size of the column by the row is A×B is printed on the photosensitive material, wherein the dot pattern has an irregularity of no more than S +10 μm in a thickness direction of the photosensitive material, and an almost circular shape not lower than 100 μm and not more than the smaller diameter either A/M or B/N when viewed from the emulsion layer side.

A marking method, where a laser beam is irradiated onto an emulsion layer having a thickness S formed on a surface of a base layer, and dot patterns in which at least the emulsion layer is melted in an almost circular shape are arrayed in a column and in a row to print a character or a mark, wherein an irradiation condition of the laser beam is determined such that the dot pattern has irregularity of no more than S+10 μm in a thickness direction of the photosensitive material, and surface roughness is in a range of 0.2 μm to 1.0 μm.

A marking method where a laser beam is irradiated onto an emulsion layer having a thickness S formed on a surface of a base layer, and dot patterns in which at least the emulsion layer is melted in an almost circular shape that is arrayed by M number in a column and N number in a row and a character or a mark where the column by the row is A×B is printed, wherein an irradiation condition of the laser beam is determined such that the dot pattern has an irregularity of no more than S+10 μm in a thickness direction of the photosensitive material, and an almost circular shape of no lower than 100 μm and no more than the smaller diameter either A/M or B/N when viewed from the emulsion layer side.

A photosensitive material wherein a film coated with a photosensitive layer on at least one side is irradiated by a laser beam to form a plurality of dot patterns including concave and convex portions, where a character or a mark is printed by an array of the dot patterns, wherein a depth of the concave portions formed in a film base directly beneath at least 80% of an amount of the dot patterns is in a range of 3 μm to 10 μm.

A marking method wherein a film coated with a photosensitive layer on at least one side is irradiated by a laser beam to form a plurality of dot patterns including concave and convex portions, and where a character or a mark is printed by an array of the dot patterns, and wherein

• an irradiation condition of the laser beam is determined such that a depth of a concave portion formed in a film base right beneath at least 80% of an amount of the dot patterns is in a range of 3 μm to 10 μm, and is irradiated.

A laser marking method where a dot pattern is formed at a certain position of a photosensitive pattern and a marking pattern including a visible character or mark is formed by a combination of the dot patterns while a laser beam is irradiated from a laser to a photosensitive material in which an emulsion layer is provided on a surface of a supporting body, and wherein an oscillation wavelength of the laser is selected on a basis of possible irradiation time of the laser beam to each dot pattern for forming a visible dot pattern.

A laser marking method where a laser beam is irradiated from a CO2 laser to a photosensitive material in which an emulsion layer is provided on a surface of a PET layer acting as a supporting body, and where a marking pattern including a visible character or mark is formed by a combination of dot patterns formed in a predetermined area, and wherein an oscillation wavelength of the CO2 laser is in a range of 9.2 μm to 9.8 μm.