Plastic barrel, optical lens assembly, imaging apparatus and electronic device

An optical lens assembly, comprising:

• a plastic barrel, comprising:
• an object-end portion comprising an outer object-end surface and an object-end hole, wherein the outer object-end surface comprises an outer flat surface orthogonal to a central axis;
• an image-end portion comprising an image-end opening;
• and
• a tube portion connecting the object-end portion and the image-end portion;
• and
• a lens module disposed in the plastic barrel and comprising a plurality of lens elements;
• wherein the plastic barrel comprises a plurality of annular grooves, which are disposed coaxially to the central axis, each of the annular grooves comprises a stepped surface, the stepped surface of each of the annular grooves comprises a plurality of orthogonal stepped surfaces orthogonal to the central axis, one of the orthogonal stepped surfaces is a groove bottom, and each of another two of the orthogonal stepped surfaces is a groove end;
• wherein when a distance parallel to the central axis between the groove bottom and the outer flat surface is greatest among distances parallel to the central axis between the orthogonal stepped surfaces and the outer flat surface, the two groove ends are disposed on two ends of the annular grooves respectively, a distance parallel to the central axis between each of the two groove ends and the outer flat surface is smaller than distances parallel to the central axis between the orthogonal stepped surfaces adjacent to thereof and the outer flat surface, and the distance parallel to the central axis between one of the two groove ends and the outer flat surface is smaller than or equal to the distance parallel to the central axis between the other one of the two groove ends and the outer flat surface;
• wherein when a distance parallel to the central axis between the groove bottom and the outer flat surface is smallest among distances parallel to the central axis between the orthogonal stepped surfaces and the outer flat surface, the two groove ends are disposed on two ends of the annular grooves respectively, a distance parallel to the central axis between each of the two groove ends and the outer flat surface is greater than distances parallel to the central axis between the orthogonal stepped surfaces adjacent to thereof and the outer flat surface, and the distance parallel to the central axis between one of the two groove ends and the outer flat surface is greater than or equal to the distance parallel to the central axis between the other one of the two groove ends and the outer flat surface;
• wherein a distance parallel to the central axis between the one of the two groove ends and the groove bottom is h, a diameter of the object-end hole is φo, and the following conditions are satisfied:
• 0.02 mm<h<0.25 mm;
• and
• φo<4.5 mm.