Imaging lens and electronic device

An imaging lens comprising:

• a plastic lens element having a central axis, and the plastic lens element comprising:
• an optically effective portion, wherein the central axis passes through a center of the optically effective portion;
• and
• a peripheral portion adjacently disposed around the optically effective portion, and the peripheral portion comprising:
• a first side surface;
• a second side surface disposed opposite to the first side surface in a direction parallel to the central axis;
• and
• a connection surface connected to the first side surface and the second side surface, and the connection surface being located farther away from the central axis than the first side surface and the second side surface;
• wherein at least one of the first side surface and the second side surface has a structural region, the plastic lens element further comprises a plurality of columnar protrusions, the plurality of columnar protrusions are disposed in the structural region and arranged in a two-dimensional array, the plurality of columnar protrusions are connected to the structural region and extend protrusively away from the structural region, each of the plurality of columnar protrusions has a bottom part and a top part that are opposite to each other, a contour of each of the bottom parts is circular-shaped, the bottom parts are connected to the structural region, and each of the top parts has an arcuate surface;
• and
• wherein a projected area of the structural region on a plane perpendicular to the central axis is A1, a number of the plurality of columnar protrusions is N1, and the following condition is satisfied:
• 250
• ⁢
• mm
• -
• 2
• <
• N
• ⁢
• 1
• /
• A
• ⁢
• 1
• <
• 1500
• ⁢
• mm
• -
• 2
• .