Microstructure for light-emitting element, and light-emitting element and illumination device including microstructure

A microstructure for a light-emitting element, comprising a plurality of microscopic convex parts each having a circular bottom surface, wherein

• the convex part has a peak on a perpendicular line at a center of the bottom surface and is defined by a generatrix connecting the peak and a circumference of the bottom surface,
• the generatrix of the convex part is formed by monotonically reducing height from the peak to the circumference of the bottom surface,
• the height of the peak of the convex part is 0.67 to 1.15 times as large as a radius of the bottom surface,
• the height of the convex part at a position of 3/4 of the radius of the bottom surface from the center of the bottom surface is 0.21 to 0.65 times as large as the radius of the bottom surface, and
• the height of the convex part at a position of 9/10 of the radius of the bottom surface from the center of the bottom surface is 0.04 to 0.38 times as large as the radius of the bottom surface.

A microstructure for a light-emitting element, comprising a plurality of microscopic concave parts each having a circular opening face, wherein

• the concave part has a bottom on a perpendicular line at a center of an opening face, and is defined by a generatrix connecting the bottom and a circumference of the opening face,
• the generatrix of the concave part is formed by monotonically increasing depth from the circumference of the opening face to the bottom,
• the depth of the bottom of the concave part is 0.65 to 1.43 times as large as the radius of the opening face,
• the depth of the concave part at a position of 3/4 of the radius of the opening face from the center of the opening face is 0.16 to 0.79 times as large as the radius of the opening face, and
• the depth of the concave part at a position of 9/10 of the radius of the opening face from the center of the opening face is 0.03 to 0.39 times as large as the radius of the opening face.