| 摘要 |
PROBLEM TO BE SOLVED: To provide optical characteristics equal to those of a lamp equipped with an aspheric lens by providing a Fresnel-shaped portion integrally formed with a lens and a flat portion therearound. SOLUTION: This lens 10 is a substantially flat glass lens including a Fresnel- shaped portion 12 and a flat portion 14 therearound. Preferably, the lens 10 uses borosilicate or soda-lime silicate, and is manufactured by an ordinary hot-glass press technique. In construction of an automobile lamp, the lens 10 is mounted on the edge of a reflector and serves as follows. The lens 10 directs light in a specified direction and closes an open top part of the reflector. This forms a lamp unit suitable for a headlamp or a fog lamp. Because no top lens is required, manufacturing costs are reduced and design flexibility increases. The lens 10 may have a circular, square, or oval shape as well as a rectangular shape. |
