| 摘要 |
PROBLEM TO BE SOLVED: To prevent a weld line from occurring in the working area in an optical lens having a biased thickness which is assembled in a projection-type projector. SOLUTION: The optical lens having the biased thickness or a thin lens center and a thick outer circumference is shaped by cooling and solidifying a resin filled in a cavity from a resin injection opening. The shaped optical lens has at least one protrusive part having a width of a flow-in opening bigger than the depth on each of right and left parts of a flange outer circumference in the range from a gate formed in the resin injection opening to the position by 180 degree apart therefrom. By this, it is possible to make the resin turning around from the resin injection opening along the circumference to the opposite side of the injection opening flow to the opposite side of the resin injection opening, and to shorten a time difference between a reaching time for the resin to flow in the opposite side of the resin injection opening from the resin injection opening via the lens center and a reaching time for the resin to turn around the circumference from the resin injection opening and flow in the opposite side of the resin injection opening. COPYRIGHT: (C)2007,JPO&INPIT |
