A ground or molded piece of glass, plastic, or other transparent material with opposite surfaces either or both of which are curved, by means of which light rays are refracted so that they converge or diverge to form an image.

• 透镜，镜片一片磨光的或塑造成的玻璃、塑料或其它透明的物质，有两个相反的表面，其中的一个或两个都成曲线形，通过这种方式可将光线折射以便聚集或发散来形成图像