1. A solid-state imaging apparatus having a pixel area including a plurality of light receiving elements, comprising:
a semiconductor substrate in which the plurality of light receiving elements are formed, and
an air gap layer arranged above the semiconductor substrate, and including a plurality of portions arranged correspondingly
to the plurality of light receiving elements and air gaps arranged between the plurality of portions and having a refractive
index lower than that of the plurality of portions, wherein
a width of the air gaps gradually increases from a central region in the pixel area toward a peripheral region in the pixel
area, the widths are to be measured at the same point along the height of each of the air gaps.