Dot film, multi-layers optic sheet and smart electric board

A dot film that enables tracking of a writing trajectory of an electronic pen so that writing is recognized and displayed on a screen or blackboard of an image device, which is formed by applying a resin mixture to a base layer of a synthetic resin, printing a printing material on a rear surface of a resin layer so as to impregnate it thereon and to form fine dots, and then separating and removing the base layer from the resin layer, and then attaching a protective film to a front surface of the separated resin layer,

• wherein the fine dots are formed on a grid line at intervals from crossing points of virtual grid lines to have a dot value, and have location information encrypted therein so as to determine location information of the electronic pen when writing with the electronic pen,
• wherein the resin mixture contains 30 to 50% by weight of a polyolefin-based resin, 15 to 25% by weight of a silicone resin, 15 to 25% by weight of an urethane methacrylate oligomer, 5 to 10% by weight of methylene diphenyl diisocyanate, 1 to 5% by weight of tetrahydrofurfuryl methacrylate, 1 to 5% by weight of polyvinylpyrrolidone, 1 to 3% by weight of 2-phenoxyethyl methacrylate, 1 to 3% by weight of polymethacrylate, 0.5 to 2% by weight of 1,4-phenylenebisoxazoline, 0.5 to 1.5% by weight of 1,4-butanediol diacrylate, 0.5 to 1.5% by weight of tetraethylene glycol dimethacrylate, 0.5 to 1.5% by weight of bis(3-ethyl-5-methyl-4-maleimidophenyl)methane, 0.5 to 1.5% by weight of N-[4-(2-benzimidazolyl)phenyl]maleimide, 0.5 to 1.5% by weight of stannous oleate, 0.5 to 1.5% by weight of dibutyltin diacetate, 0.5 to 1.5% by weight of N,N′-bis(2-methyl-1-imidazolyl ethyl) urea, 0.1 to 1.0% by weight of p-toluenesulfonyl hydrazide, 0.1 to 1.0% by weight of epichlorohydrin, and 0.5 to 1.0% by weight of an antistatic agent,
• wherein the protective film is made of PET or polycarbonate, is detachably attached and thus is provided to be replaced, and has a coating layer applied with a thickness of 0.1 to 0.5 mm on an outer surface thereof to provide an anti-glare function and a UV blocking function, and
• wherein the coating layer includes 30 to 50 parts by weight of acrylate monomer, 1 to 5 parts by weight of 4,4′-diaminobenzophenone, 15 to 20 parts by weight of tris[(3-mercaptopropionyloxy)-ethyl]-isocyanurate (TEMPIC), 1 to 5 parts by weight of menthyl anthranilate, 1 to 5 parts by weight of 3-glycidoxypropylmethyldiethoxysilane, 1 to 5 parts by weight of a polyether siloxane copolymer, 0.1 to 0.5 parts by weight of a dispersing agent, 0.1 to 0.5 parts by weight of an antifoaming agent, and 0.1 to 0.5 parts by weight of a thickener, based on 100 parts by weight of polyurethane acrylate oligomer.