# US 2025/0145837 A1 · Anti-fog sheet structure and helmet > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2025/0145837 A1 - Document ID: US20250145837A1 - Status: Published application - Kind: A1 - Application number: 18/911,418 - Filed: 2024-10-10 - Published: 2025-05-08 - Earliest claimed: 2023-11-07 - Assignees: Sharp Display Technology Corporation - Applicants: Sharp Display Technology Corporation - Inventors: Kenichiro NAKAMATSU; Mitsuaki Sugine; Hideya Hashii; Tokio Taguchi - Web page: https://patentgrep.com/patent/US20250145837A1 ## CPC - C09D 5/1668: {Vinyl-type polymers} - A42B 3/0406: {Accessories for helmets} - A42B 3/24: with means for avoiding fogging or misting - C09D 4/00: Coating compositions, e.g. paints, varnishes or lacquers, based on organic non-macromolecular compounds having at least one polymerisable carbon-to-carbon unsaturated bond {; Coating compositions, based on monomers of macromolecular compounds of groups C09D183/00 - C09D183/16} - C09D 133/14: of esters containing halogen, nitrogen, sulfur or oxygen atoms in addition to the carboxy oxygen - C09D 135/02: Homopolymers or copolymers of esters (C09D135/06, C09D135/08 take precedence) - C08F 222/104: {of tetraalcohols, e.g. pentaerythritol tetra(meth)acrylate} - 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) - A42B: HATS; HEAD COVERINGS (headbands A41D20/00; head-scarves A41D23/00) - C08F: MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS ## Abstract An anti-fog sheet structure includes: a substrate made of polycarbonate, a first synthetic polymer film formed on a first main surface side of the substrate, and a second synthetic polymer film formed on a second main surface side, wherein the first synthetic polymer film has, on its surface, a plurality of first bumps having an equivalent circular area diameter Dp1 in the range of more than 50 nm and less than 500 nm, the second synthetic polymer film has, on its surface, a plurality of second bumps having an equivalent circular area diameter Dp2 in the range of more than 20 nm and less than 500 nm, and the first synthetic polymer film is formed from a cured product of a photocurable resin containing 30 mass % or more of ethoxylated pentaerythritol tetraacrylate. ## Claims ### Claim 1 An anti-fog sheet structure comprising: a substrate made of a transparent plastic, a first synthetic polymer film formed on a first main surface side of the substrate, and a second synthetic polymer film formed on a second main surface side of the substrate on an opposite side from a first main surface, wherein the first synthetic polymer film has, on its surface, a plurality of first bumps having an equivalent circular area diameter Dp1 in a range of more than 50 nm and less than 500 nm as viewed in a normal direction of the first synthetic polymer film, the second synthetic polymer film has, on its surface, a plurality of second bumps having an equivalent circular area diameter Dp2 in a range of more than 20 nm and less than 500 nm as viewed in a normal direction of the second synthetic polymer film, the first synthetic polymer film is formed from a cured product of a photocurable resin containing 30 mass % or more of ethoxylated pentaerythritol tetraacrylate, the second synthetic polymer film is formed from a cured product of a photocurable resin, and the anti-fog sheet structure has anti-fog properties such that a time for a visible light in-line transmittance of the first synthetic polymer film to decrease to 80% of an initial value with the surface of the first synthetic polymer film in contact with saturated water vapor at 50° C. is 90 seconds or longer. ### Claim 2 (depends on 1) The anti-fog sheet structure according to claim 1, wherein, when a height of the plurality of first bumps is represented by Dh1, Dh1 is 50 nm or more, and an aspect ratio A1=Dh1/Dp1 is less than 1.0; and when a height of the plurality of second bumps is represented by Dh2, an aspect ratio A2=Dh2/Dp2 is 1.0 or more. ### Claim 3 (depends on 2) The anti-fog sheet structure according to claim 2, wherein the height Dh1 of the plurality of first bumps satisfies 150 nm≤Dh1≤300 nm. ### Claim 4 (depends on 2) The anti-fog sheet structure according to claim 2, wherein the height Dh2 of the plurality of second bumps satisfies 150 nm≤Dh2≤200 nm. ### Claim 5 (depends on 2) The anti-fog sheet structure according to claim 2, wherein the aspect ratio A2=Dh2/Dp2 is 1.5 or less. ### Claim 6 (depends on 2) The anti-fog sheet structure according to claim 2, wherein the height Dh1 of the plurality of first bumps is greater than or equal to the height Dh2 of the plurality of second bumps. ### Claim 7 (depends on 1) The anti-fog sheet structure according to claim 1, wherein the surface of the first synthetic polymer film has a contact angle to water of 20° or more. ### Claim 8 (depends on 1) The anti-fog sheet structure according to claim 1, wherein the first synthetic polymer film is formed from a cured product of the photocurable resin further containing urethane acrylate. ### Claim 9 (depends on 8) The anti-fog sheet structure according to claim 8, wherein the urethane acrylate is such that a cured product of a mixture of 70 mass % of the urethane acrylate and 30 mass % of 2-(2-vinyloxyethoxy)ethyl acrylate monomer has a water absorption rate of more than 2.0%. ### Claim 10 (depends on 1) The anti-fog sheet structure according to claim 1, further comprising a third synthetic polymer film formed between the first main surface of the substrate and the first synthetic polymer film, wherein the third synthetic polymer film has, on its surface, a plurality of third bumps having an equivalent circular area diameter Dp3 in a range of more than 20 nm and less than 500 nm as viewed in a normal direction of the third synthetic polymer film. ### Claim 11 (depends on 1) The anti-fog sheet structure according to claim 1, wherein the anti-fog sheet structure has a haze value of 1.0 or less. ### Claim 12 (depends on 1) The anti-fog sheet structure according to claim 1, wherein an absolute value of a* and an absolute value of b* of transmitted light in an L*a*b* color space are each independently 1.0 or less. ### Claim 13 (depends on 1) A helmet comprising a shield and a shell, wherein the helmet further comprises an anti-fog sheet structure inside the shield with a gap therebetween, the anti-fog sheet structure is the anti-fog sheet structure according to claim 1 and configured such that the first synthetic polymer film comes inside when the helmet is worn.