plano-convex

Two large plano-convex lenses (C), called condensing lenses, are placed near the lamp to concentrate the light upon the "slide" S.

In fact, a plano-convex crystal lens has been found among the ruins of Nineveh.

In most plano-convex examples, the plane face is unmodified except for retouch.

The two examples with plano-convex cross-sections were unmodified on the plano face except for retouch along the edges.

The oldest type, whether baked or crude, is plano–convex in form, and uninscribed.