Optical element with annular light-collecting area forming an annular image outside itself

Abstract

An optical element to be interposed between an optical transmission line and a light-emitting element or a light-receiving element such that an optical path from one side to the other passes through the optical element is provided. At least one surface of the optical element is provided with a first light-collecting area and a second light-collecting area. A surface of the first light-collecting area is configured such that light from the one side is received by the other side. A surface of the second light-collecting area is an annular surface or a part of the annular surface and is configured such that light that has passed through the second light-collecting area forms an image in the shape of a ring or a part of the ring at a position between the optical element and the other side.

Dependencies are inferred from the claim text.