A mirror , lens , or combination of lenses used to gather light and direct it upon an object or through a projection lens 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
This setup , known as a conoscope , is shown in figure 14 . 2 and consists of two stress - free plane - convex lenses a and b and a diaphragm c having a small aperture 此装置称为锥光镜，如图14 2所示，它由a和b两个无应力平凸透镜和一个带小孔的光阑c组成。
Since lenticular clouds look like one or more convex lens , they could sometimes be misinterpreted as flying saucers or unidentified flying objects , and so they are commonly known as " flying saucer clouds " 由于这类荚状云形状像一块或多块凸透镜，有时候被误会为飞碟或不明飞行物体，所以亦俗称飞碟云。
Analysis showed this might be due to the fact that a black hole passed in front of the star . the gravitation of a black hole can function as a convex lens and focus starlight , resulting in transience increase of apparent brightness of the star 分析显示，这很可能是因为有一个黑洞在恒星前面经过，黑洞的引力会聚了星光，就像凸透镜把光线聚焦一样，使恒星的视亮度增加。
The interferometric zone plate is the essential of hoes , which is the interference between plane wave and sphere wave , can focus the light beam by diffraction , instead of the way which conventional lens or concave mirrors do 摘要干涉式波带板系由平面波和球面波两道光波干涉而成，为研究全像光学元件的基础，其可经由绕射作用达到聚焦效果，犹如使用传统凸透镜或凹面镜所产生的效果。
The laser beams from m - z interferometer will focus on three different dots after going through the positive lens , and the prisms were placed on these dots . owing to the deviation of these prisms , three interferograms will be separated each other when they reach the image board 由干涉仪射出的三束光经凸透镜会聚于空间位置不同的点，把光楔放置在这些点上可使三束光在空间上彼此分开，利用ccd相机可记录下三幅干涉图。
This paper analyses and explains several interferential images arising from autocollimation , and lays more emphasis on the analysis of the convex with identical property to a spherical reflector , introduces the relatios between reflection images and autocollimation images , and expounds how to form to judgment about interferential images 摘要对自准值法测量时出现的几个干扰像进行分析、解释，著重分析了凸透镜也具有球面反射镜的性质，导出反射像和自准值法成像的关系，及若何判断干扰像。
