聚光器用于聚光并将光引向某物体或通过一凸透镜组的镜子、透镜或透镜组 A mirror, lens, or combination of lenses used to gather light and direct it upon an object or through a projection lens.
色差由于光学器件（如透镜）的物理缺陷而造成的不完美成象 An imperfect image caused by a physical defect in an optical element, as in a lens.
他用一面凸透镜把阳光在纸上聚成焦点。 He focused the sun's ray on a piece of paper with a burning-glass.
