Wavelength conversion sheet, backlight, and liquid crystal display device

Abstract

Provided is a wavelength conversion sheet having excellent close adhesion between a phosphor layer and a primer layer even after a long-term environment test. A wavelength conversion sheet, including: a phosphor layer including a phosphor; and a film for a wavelength conversion sheet provided on at least one surface side of the phosphor layer, wherein the film for a wavelength conversion sheet includes at least a base material layer and a primer layer laminated thereon, and the primer is in contact with the phosphor layer, the phosphor layer and the primer layer include an element X, and CPR/CQD satisfies 0.10 or less, where CQD (atomic %) is an average value of proportions of the element X in the phosphor layer within a region from an interface between the primer layer and the phosphor layer to 400 nm in a thickness direction of the phosphor layer, obtained by X-ray photoelectron spectroscopy, and where CPR (atomic %) is a proportion of the element X in the primer layer at any depth within a region between 20 nm or more and 40 nm or less from the interface in a thickness direction of the primer layer, obtained by X-ray photoelectron spectroscopy.

Dependencies are inferred from the claim text.