Patent ID: 8354206

Claim:
A method of generating photomask data used to fabricate a photomask, which is to be used for manufacturing a microlens array by photolithography, the photomask having a microlens pattern including light-shielding portions and non-light-shielding portions for forming a microlens, in each of a plurality of two-dimensionally arranged rectangular regions, each rectangular region including a surrounding region having four sides of the rectangular region as outer edges and a primary region having boundaries that are inner edges of the surrounding region, the surrounding region being configured by four strip regions each of the four strip regions including one of the four sides as a part of a contour of each strip region, and a width between each outer edge and each corresponding inner edge of the surrounding region being not more than ½ of a wavelength of exposure light to be used in the photolithography, the method comprising: a first step of determining a layout of light-shielding portions and non-light-shielding portions in the primary region; and a second step of determining a layout of light-shielding portions and non-light-shielding portions in the surrounding region so that a first density of the light-shielding portions defined by (an area of light-shielding portions)/((an area of light-shielding portions)+(an area of non-light-shielding portions)) is set to fall within a range from 0% to 15% (both inclusive).