16-07-2020 дата публикации
Номер: US20200225387A1
Provided are a reflective sheet having selective reflection in a wide wavelength range and a small change in tint depending on angles at which light is visually recognized, a decorative sheet, and a method of manufacturing a reflective sheet, the reflective sheet including a pitch gradient layer in which a helical pitch changes in a thickness direction of the layer. The reflective sheet includes at least one cholesteric liquid crystal layer having wavelength selective reflection properties, in which at least one of the cholesteric liquid crystal layers is a pitch gradient layer in which a helical pitch changes in a thickness direction, a half-width of an integral reflection spectrum of the reflective sheet is 100 nm or longer, and in a case where a wavelength on a short wavelength side that defines the half-width is represented by λα, a wavelength on a long wavelength side that defines the half-width is represented by λβ, a center wavelength that defines the half-width is represented by λ, λ=(λα+λ/2, and λ=(λ+λβ)/2, the following Expressions (1) and (2) are satisfied. 1. A reflective sheet comprising:at least one cholesteric liquid crystal layer having wavelength selective reflection properties,wherein at least one of the cholesteric liquid crystal layers is a pitch gradient layer in which a helical pitch changes in a thickness direction,a half-width of an integral reflection spectrum of the reflective sheet is 100 nm or longer, and{'sub': C', '1', 'C', '2', 'C, 'claim-text': [{'br': None, 'i': I−R', 'I−R, 'sub': 1', '2, '(λ)>(λ) \u2003\u2003Expression (1),'}, {'br': None, 'i': SCE', 'I−R', 'I−R, 'sub': 1', '1', '2', '2, '(λ)/(λ)>SCE(λ)/(λ) \u2003\u2003Expression (2),'}], 'in a case where a wavelength on a short wavelength side that defines the half-width is represented by λαa, a wavelength on a long wavelength side that defines the half-width is represented by λβ, a center wavelength that defines the half-width is represented by λ, λ=(λα+λ)/2, and λ=(λ+λβ)/2, the ...
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