This is made possible through something called a lenticular lens – a corrugated sheet in which each ridge is made up of a convex – or outward-curving – lens.

这是通过一种叫做柱状透镜东西实现，柱状透镜是一种波纹状薄板，其每个由透镜（即向外弯曲透镜）组成。

And if you work it out, you would probably have a weak convex lens with about an 18-inch focal length in combination with a pretty strong concave lens with a focal length of about 6 inches.

如果你一下，你可能会得到一个焦距大约为18英寸透镜，与一个焦距约为6英寸强凹透镜组合。

But the idea was that you would use a very large convex lens at the end, the object glass, not because That changes optical power, but because you're polishing only the very central part.

但想法是你会在末端使用一个非常大透镜，即物镜， 不是因为这会改变光学功率，而是因为你只打磨中央部分。

Say we have a lens that has a spherical face on both sides, known as a convex lens.

假设我们有一个具有球面镜头 两侧，称为透镜。

There are instances in which towers were set up with a mirror inside of a dark room and sometimes with a convex lens in the aperture.

在一些情况下，人们会在黑暗房间内设置带有镜子塔楼，有时还会在开口安装透镜。