He focused the sun's rays on a paper with a burning glass.

他用一面凸透镜把阳光聚焦在纸上。

A physiotherapeutic apparatus for preventing and treating near sighted eye has a convex lens used as objective lens, lens cone, eyepiece, headgear and lens set.

一种防眼理疗器，它有作为物镜凸透镜、镜筒、目镜，还有头套和透镜，它用于人们在距离上长时间用眼时戴在眼上，可以使被物楚、放大和变远。