LENS FOR USE IN FLASH LAMP

摘要

A lens includes an incidence surface and an emission surface. The emission surface includes an effective area and a non-effective area around the effective area. The non-effective area includes a first effective area located at the center of the effective area and a second effective area around the first effective area. The first effective area is three fifths of the effective area. A number of recesses formed on the surface of the first effective area and substantially over the entire first effective area.