Disclosed is a lens, which has a convex surface, a concave surface and
a flange that is formed around the lens to be projected in a radial direction perpendicular
to an optical axis and to be continued from the convex surface. The flange is provided
with a groove formed on the side of the convex surface that extends from the outer
edge of the convex surface toward the outer edge of the flange. When the lens is
pulled up from a solution of coating material, the unnecessary solution that collects
at a lower area of the convex surface drips from the lens through the groove. This
prevents a formation of a puddle on the convex surface.