# US 11,442,209 B2 · Multilayer film stack > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,442,209 B2 - Document ID: US11442209B2 - Status: Granted - Kind: B2 - Application number: 16/627,978 - Filed: 2018-07-04 - Published: 2020-04-30 - Granted: 2022-09-13 - Earliest claimed: 2017-07-07 - Assignees: Toyobo Co., Ltd. - Applicants: Toyobo Co., Ltd. - Inventors: Amane Hirose; Mitsuo Tojo - Web page: https://patentgrep.com/patent/US11442209B2 ## CPC - G02B 5/305: {including organic materials, e.g. polymeric layers} - B32B 7/02: Physical, chemical or physicochemical properties - B32B 7/022: Mechanical properties - B32B 27/08: of synthetic resin - B32B 27/36: comprising polyesters - G02B 5/30: Polarising elements (light-modulating devices with active elements G02F1/00) - G02B 5/3083: {Birefringent or phase retarding elements (G02B5/3008, G02B5/3016 take precedence; systems for polarisation control G02B27/286; manufacturing phase modulating patterns by lithographic processes G03F7/001)} - G02F 1/1335: Structural association of cells with optical devices, e.g. polarisers or reflectors - G02F 1/133536: {Reflective polarizers (G02F1/13362 takes precedence)} - B32B 2250/05: 5 or more layers - B32B 2250/42: Alternating layers, e.g. ABAB(C), AABBAABB(C) - G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS - B32B: LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM - 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 ## Abstract The invention provides a multilayer laminated film containing a multilayer laminated structure of alternately laminated first and second layers, and a thick film layer in contact therewith. The multilayer laminated structure has a layer thickness profile in terms of the physical thickness of repeating first and second layers. The layer thickness profile has a monotonously increasing thickness region and a thin layer region, which has at least three repeating units, a L2/L1 ratio of 0.85 or less, and a A2/L1 ratio of 0.70 or less, where L1 is the maximum repeating unit thickness in the monotonously increasing thickness region, L2 is the maximum repeating unit thickness in the thin layer region, and A2 is the average repeating unit thickness in the thin layer region. The thin layer region is on the thicker side of the monotonously increasing thickness region and in contact with the thick film layer. ## Claims ### Claim 1 A multilayer laminated film comprising at least one multilayer laminated structure in which a first layer containing a first resin and a second layer containing a second resin are alternately laminated, and at least one outermost layer having a thickness of 1-25 μm that is in contact with the multilayer laminated structure, wherein when the multilayer laminated film comprises a plurality of the multilayer laminated structures, the multilayer laminated film comprises at least one intermediate layer; the multilayer laminated structure has a layer thickness profile in terms of a physical thickness of a repeating unit having one first layer and one second layer, and the layer thickness profile has a monotonously increasing thickness region and a thin layer region; the thin layer region has at least three repeating units and is a region in which the L2/L1 ratio is 0.85 or less, where L2 is the maximum repeating unit thickness in the thin layer region, and L1 is the maximum repeating unit thickness in the monotonously increasing thickness region, and the A2/L1 ratio is 0.70 or less, where A2 is the average repeating unit thickness in the thin layer region, and L1 is the maximum repeating unit thickness in the monotonously increasing thickness region; and the thin layer region is on the thicker side of the monotonously increasing thickness region and is in direct contact with the outermost layer or intermediate layer. ### Claim 2 (depends on 1) The multilayer laminated film according to claim 1, wherein the L2/S1 ratio exceeds 1.0, where L2 is the maximum repeating unit thickness in the thin layer region, and S1 is the minimum repeating unit thickness in the monotonously increasing thickness region. ### Claim 3 (depends on 1) The multilayer laminated film according to claim 1, wherein the first layer is birefringent, the second layer is isotropic, and the film is capable of reflecting light at a wavelength of 380 to 780 nm by optical interference of the layers. ### Claim 4 (depends on 1) A luminance-improving member comprising the multilayer laminated film according to claim 1. ### Claim 5 (depends on 1) A polarizer for a liquid crystal display, the polarizer comprising the multilayer laminated film according to claim 1. ### Claim 6 (depends on 2) The multilayer laminated film according to claim 2, wherein the first layer is birefringent, the second layer is isotropic, and the film is capable of reflecting light at a wavelength of 380 to 780 nm by optical interference of the layers. ### Claim 7 (depends on 2) A luminance-improving member comprising the multilayer laminated film according to claim 2. ### Claim 8 (depends on 3) A luminance-improving member comprising the multilayer laminated film according to claim 3. ### Claim 9 (depends on 6) A luminance-improving member comprising the multilayer laminated film according to claim 6. ### Claim 10 (depends on 2) A polarizer for a liquid crystal display, the polarizer comprising the multilayer laminated film according to claim 2. ### Claim 11 (depends on 3) A polarizer for a liquid crystal display, the polarizer comprising the multilayer laminated film according to claim 3. ### Claim 12 (depends on 6) A polarizer for a liquid crystal display, the polarizer comprising the multilayer laminated film according to claim 6. ### Claim 13 (depends on 1) The multilayer laminated film according to claim 1, wherein the thin layer region has 3 to 15 repeating units. ### Claim 14 (depends on 6) The multilayer laminated film according to claim 6, wherein the thin layer region has 3 to 15 repeating units. ### Claim 15 (depends on 13) A luminance-improving member comprising the multilayer laminated film according to claim 13. ### Claim 16 (depends on 14) A luminance-improving member comprising the multilayer laminated film according to claim 14. ### Claim 17 (depends on 13) A polarizer for a liquid crystal display, the polarizer comprising the multilayer laminated film according to claim 13. ### Claim 18 (depends on 14) A polarizer for a liquid crystal display, the polarizer comprising the multilayer laminated film according to claim 14.