Abstract: A lens is provided. The lens comprises a lens body. The lens body is substantially in a shape of a circular table. A small end of the lens body is provided with a concave inner light source accommodation space. The inner surface of the light source accommodation space is an incident surface of light. A surface of a large end of the lens body is an exit surface, and a side surface of the lens body is a reflecting surface. A bottom of the light source accommodation space is provided with a cylindrical protrusion. A cross section dimension of the light source accommodation space gradually decreases, from the small end of the lens to the large end of the lens. The cylindrical protrusion is formed by protrusion from the bottom of the light source accommodation space toward the small end of the lens body.

Abstract: A lens is provided. The lens comprises a lens body. The lens body is substantially in a shape of a circular table. A small end of the lens body is provided with a concave inner light source accommodation space. The inner surface of the light source accommodation space is an incident surface of light. A surface of a large end of the lens body is an exit surface, and a side surface of the lens body is a reflecting surface. A bottom of the light source accommodation space is provided with a cylindrical protrusion. A cross section dimension of the light source accommodation space gradually decreases, from the small end of the lens to the large end of the lens. The cylindrical protrusion is formed by protrusion from the bottom of the light source accommodation space toward the small end of the lens body.