Manufacturing method of the functional membrane and the functional membrane

A functional membrane which contains an inorganic material as a main component thereof and has a fine uneven structure on a surface thereof, wherein

• a plurality of protruding portions which constitute the fine uneven structure are formed in a stair shape having one or more stairs in a vertical cross-sectional shape of the functional membrane along a thickness direction of the functional membrane,
• when Mohs hardness of the inorganic material is denoted as X and the number of the stairs of the protruding portions is denoted as Y, following formula (I) is satisfied,
• an average height from the lowest bottom surface of the protruding portions of the lowermost stair to the highest top surface of the protruding portions of the uppermost stair is 1 μm or less, and
• a reflectance adjustment layer made of a material different from a material of an uneven layer having the fine uneven structure is formed between a base material and the uneven layer.
• 10
• ≦
• X
• ×
• Y
• Formula
• ⁢
• (
• I
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