Lens barrel and image pickup apparatus

A lens barrel assembly comprising:

• a plastic lens provided with a flange part having first, second, third, and fourth fixed protrusions;
• and
• a lens holding portion adapted for holding the lens, said lens holding portion having first, second, third, and fourth supporting holes respectively corresponding to the first, second, third, and fourth fixed protrusions of the lens,
• in which the first, second, and third fixed protrusions are arranged in an outer peripheral portion of the flange part at predetermined intervals, and the fourth fixed protrusion is arranged on a line connecting the first fixed protrusion and a center of the lens;
• in which the first supporting hole includes an opening having substantially a same size as the first fixed protrusion, the second and third fixed protrusions have approximately a same size and the second and third supporting holes have approximately a same size and the second and third supporting holes include openings larger than the second and third fixed protrusions, and the fourth supporting hole includes an elongated hole, and
• in which the lens is further provided with a gate part located outwardly adjacent to the first fixed protrusion such that said gate part protrudes outwardly from the flange part on the line connecting the first fixed protrusion and the center of the lens, said gate part being an inlet for injecting resin into a mold when molding the lens.

A lens barrel comprising:

• a lens holding portion having first, second, third, and fourth supporting holes,
• said lens holding portion being adapted for holding a lens provided with a flange part having first, second, third, and fourth fixed protrusions which respectively correspond to the first, second, third, and fourth supporting holes,
• in which the first, second, and third fixed protrusions are arranged in an outer peripheral portion of the flange part at predetermined intervals, and the fourth fixed protrusion is arranged on a line connecting the first fixed protrusion and a center of the lens;
• in which the first supporting hole includes an opening having substantially a same size as the first fixed protrusion, the second and third fixed protrusions have approximately a same size and the second and third supporting holes have approximately a same size and the second and third supporting holes include openings larger than the second and third fixed protrusions, and the fourth supporting hole includes an elongated hole, and
• in which the lens is further provided with a gate part located outwardly adjacent to the first fixed protrusion such that said gate part protrudes outwardly from the flange part on the line connecting the first fixed protrusion and the center of the lens, said gate part being an inlet for injecting resin into a mold when molding the lens.