A focusing optical part, including a plastic body, suitable for being delivered on a tape and reel and mounted on a PCB by an automated mounting machine, the plastic body including a concave mirror including a center aperture input surface through which light enters the plastic body, a convex mirror opposite the center aperture, wherein the concave mirror and the convex mirror form a reflective objective that reflects and focuses the light inside the plastic body, and an exit surface surrounding the convex mirror, through which focused light exits the plastic body.