To provide a method for manufacturing a microlens with high manufacturing accuracy.
A gray scale mask GSM1 for exposing a circular region in a center portion of a microlens has a circular effective region 1a in its center portion. A gray scale mask GSM2 for exposing an annular region adjacent to the center circular portion of the microlens has an annular effective region 2a in its intermediate portion. A gray scale mask GSM3 for exposing a peripheral annular region of the microlens has an annular effective region 3a in its peripheral portion. The effective regions 1a and 2a, and 2a and 3a are formed in such a manner that the boundaries are mutually superimposed as shown in the left side of Fig.1. The gray scale value of the GSM in the superimposed range is controlled in such a manner that upon carrying out superimposed exposure, a resist is exposed with an appropriate exposure light quantity to obtain a target SAG amount. Thus, generation of a level difference in a seam of the GSM can be prevented.
COPYRIGHT: (C)2008,JPO&INPIT
YONETANI NOBORU
KIKUCHI HIROFUMI
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