Barrier film for wavelength conversion sheet, wavelength conversion sheet, backlight, and liquid crystal display device using barrier film, and method for selecting barrier film for wavelength conversion sheet

A barrier film for a wavelength conversion sheet, the barrier film comprising a base material film, a barrier layer, and a primer layer in presented order, wherein the barrier film satisfies the following condition 1′:

• <Condition 1′>
• A surface of the barrier film on a side having the primer layer with respect to the barrier layer is defined as a surface 1′;
• an elevation of the surface 1′ is measured at intervals of 1 mm to obtain elevation data about the surface 1′;
• a contour curve of the surface 1′ determined by the elevation data is defined as a contour curve 1′;
• at least a part of the surface 1′ comprises at least one or more irregularity 1′ having a height difference between an adjacent peak and valley of 0.001 mm or more and 0.600 mm or less in the contour curve 1′ in a predetermined direction;
• when a height difference and a width of the irregularity 1′ are defined as H [mm] and W [mm], respectively, the following expression (1′):
• H
• /
• W
• 2
• ≤
• 1.5
• ×
• 10
• -
• 5
• (
• 1
• ′
• )
• is satisfied.

A method for selecting a barrier film for a wavelength conversion sheet, the barrier film comprising a first base material film, a second base material film, a barrier layer, a primer layer, and an adhesive layer positioned between the first base material film and the second base material film, wherein

• a requirement for selecting is to satisfy the following condition 1:
• <Condition 1>
• A surface of the barrier film on a side having the primer layer with respect to the adhesive layer is defined as a surface 1;
• an elevation of the surface 1 is measured at intervals of 1 mm to obtain elevation data about the surface 1;
• a contour curve of the surface 1 determined by the elevation data is defined as a contour curve 1;
• at least a part of the surface 1 comprises at least one or more irregularity 1 having a height difference between an adjacent peak and valley of 0.001 mm or more and 0.600 mm or less in the contour curve 1 in a predetermined direction;
• when a height difference and a width of the irregularity 1 are defined as H [mm] and W [mm], respectively, the following expression (1):
• H
• /
• W
• 2
• ≤
• 1.5
• ×
• 10
• -
• 5
• (
• 1
• )
• is satisfied.

A method for selecting a barrier film for a wavelength conversion sheet, the barrier film comprising a base material film, a barrier layer, and a primer layer in presented order, wherein

• a requirement for selecting is to satisfy the following condition 1′:
• <Condition 1′>
• A surface of the barrier film on a side having the primer layer with respect to the barrier layer is defined as a surface 1′;
• an elevation of the surface 1′ is measured at intervals of 1 mm to obtain elevation data about the surface 1′;
• a contour curve of the surface 1′ determined by the elevation data is defined as a contour curve 1′;
• at least a part of the surface 1′ comprises at least one or more irregularity 1′ having a height difference between an adjacent peak and valley of 0.001 mm or more and 0.600 mm or less in the contour curve 1′ in a predetermined direction;
• when a height difference and a width of the irregularity 1′ are defined as H [mm] and W [mm], respectively, the following expression (1′):
• H
• /
• W
• 2
• ≤
• 1.5
• ×
• 10
• -
• 5
• (
• 1
• ′
• )
• is satisfied.