# US 11,906,865 B2 · Reflective sheet and transfer film for reflective sheet > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,906,865 B2 - Document ID: US11906865B2 - Status: Granted - Kind: B2 - Application number: 17/487,490 - Filed: 2021-09-28 - Published: 2022-01-13 - Granted: 2024-02-20 - Earliest claimed: 2019-03-29 - Assignees: FUJIFILM Corporation - Applicants: FUJIFILM Corporation - Inventors: Ryuji Saneto; Akira Yamamoto; Hideki Kaneiwa; Makoto Ishiguro; Michio Nagai - Web page: https://patentgrep.com/patent/US11906865B2 ## CPC - G02B 5/3016: {involving passive liquid crystal elements (optical properties of liquid crystals G02F1/0063; polarising elements associated with active liquid crystal devices G02F1/133528)} - G02F 1/13718: {based on a change of the texture state of a cholesteric liquid crystal} - B32B 7/023: Optical properties - B32B 7/12: using interposed adhesives or interposed materials with bonding properties - B32B 27/08: of synthetic resin - B32B 27/36: comprising polyesters - B32B 27/365: {comprising polycarbonates} - G02B 5/08: Mirrors {(vehicle mirrors involving special optical features B60R1/08)} - B29D 11/0073: {Optical laminates} - B29D 11/00788: {Producing optical films} - B32B 2255/10: on synthetic resin layer or on natural or synthetic rubber layer - B32B 2255/26: Polymeric coating - B32B 2307/416: Reflective - B32B 2307/536: Hardness - B32B 2307/584: Scratch resistance - B32B 2307/732: Dimensional properties - B32B 2451/00: Decorative or ornamental articles - G02B 1/14: Protective coatings, e.g. hard coatings - G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS - G02F: OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS - B32B: LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM - B29D: PRODUCING PARTICULAR ARTICLES FROM PLASTICS OR FROM SUBSTANCES IN A PLASTIC STATE (making granules B29B9/00; making preforms B29B11/00) ## Abstract Provided are a reflective sheet including a cholesteric liquid crystal layer and having excellent reflection wavelength range, diffuse reflectivity, reflectivity, hardness, and scratch resistance; and a transfer film for a reflective sheet that is used for the reflective sheet. The reflective sheet includes a substrate, an adhesive layer, a cholesteric liquid crystal layer, and a hard coat layer in this order, in which in a cross-section of the cholesteric liquid crystal layer observed, at least a part of bright portions and dark portions has a flapping structure, the cholesteric liquid crystal layer has a pitch gradient structure in which a helical pitch changes in a thickness direction, and the helical pitch on the adhesive layer side is larger than that on the hard coat layer side. ## Claims ### Claim 1 A reflective sheet comprising, in the following order: a substrate; an adhesive layer; a cholesteric liquid crystal layer obtained by immobilizing a cholesteric liquid crystalline phase; and a hard coat layer, wherein in a cross-section of the cholesteric liquid crystal layer observed with a scanning electron microscope, at least a part of bright portions and dark portions derived from the cholesteric liquid crystalline phase has a flapping structure, the cholesteric liquid crystal layer has a pitch gradient structure in which a helical pitch changes in a thickness direction, and the helical pitch on the adhesive layer side is larger than that on the hard coat layer side. ### Claim 2 (depends on 1) The reflective sheet according to claim 1, wherein as the cholesteric liquid crystal layer, a first cholesteric liquid crystal layer and a second cholesteric liquid crystal layer where a selective reflection center wavelength is the same as that of the first cholesteric liquid crystal layer and a turning direction of circularly polarized light to be selectively reflected is opposite to that of the first cholesteric liquid crystal layer are provided. ### Claim 3 (depends on 1) The reflective sheet according to claim 1, wherein in a case where light is emitted from the hard coat layer side, an integral reflectivity with respect to light having a wavelength of 450 nm is 50% to 90% and an integral reflectivity with respect to light having a wavelength of 500 nm is 30% to 80%. ### Claim 4 (depends on 1) The reflective sheet according to claim 1, wherein a thickness of the adhesive layer is 30 μm or less. ### Claim 5 (depends on 1) The reflective sheet according to claim 1, wherein the adhesive layer is a layer obtained by curing an ultraviolet curable adhesive. ### Claim 6 (depends on 1) The reflective sheet according to claim 1, wherein the hard coat layer and the cholesteric liquid crystal layer are directly laminated. ### Claim 7 (depends on 1) The reflective sheet according to claim 1, wherein the hard coat layer is a layer including a polymer obtained by polymerization of a monomer having three or more polymerizable groups. ### Claim 8 (depends on 1) The reflective sheet according to claim 1, wherein a thickness of the hard coat layer is 1 μm or more. ### Claim 9 A transfer film for a reflective sheet comprising, in the following order: a peelable support; a hard coat layer; and a cholesteric liquid crystal layer obtained by immobilizing a cholesteric liquid crystalline phase, wherein in a cross-section of the cholesteric liquid crystal layer observed with a scanning electron microscope, at least a part of bright portions and dark portions derived from the cholesteric liquid crystalline phase has a flapping structure, and the cholesteric liquid crystal layer has a pitch gradient structure in which a helical pitch changes in a thickness direction, and the helical pitch on a side opposite to the hard coat layer is larger than that on the hard coat layer side. ### Claim 10 (depends on 9) The transfer film for a reflective sheet according to claim 9, wherein as the cholesteric liquid crystal layer, a first cholesteric liquid crystal layer and a second cholesteric liquid crystal layer where a selective reflection center wavelength is the same as that of the first cholesteric liquid crystal layer and a turning direction of circularly polarized light to be selectively reflected is opposite to that of the first cholesteric liquid crystal layer are provided. ### Claim 11 (depends on 9) The transfer film for a reflective sheet according to claim 9, wherein the hard coat layer and the cholesteric liquid crystal layer are directly laminated. ### Claim 12 (depends on 9) The transfer film for a reflective sheet according to claim 9, wherein the hard coat layer is a layer including a polymer obtained by polymerization of a monomer having three or more polymerizable groups. ### Claim 13 (depends on 9) The transfer film for a reflective sheet according to claim 9, wherein a thickness of the hard coat layer is 1 μm or more. ### Claim 14 (depends on 2) The reflective sheet according to claim 2, wherein in a case where light is emitted from the hard coat layer side, an integral reflectivity with respect to light having a wavelength of 450 nm is 50% to 90% and an integral reflectivity with respect to light having a wavelength of 500 nm is 30% to 80%.