projected bundle

But what amazes people is that when a bundle of rays is projected onto the surface of the mirror, which, in turn, reflects the light on the wall, the patterns and inscriptions on the backside are shown in the ring of the light, as if they had penetrated the whole thickness of the mirror.

奇怪的是，当一束光线照到镜面，。反射投影在墙壁上，墙上的光亮圈内竟出现铜镜背面的图案和文字，好像从镜背“透”过来的，故称“透光镜”。

互联网摘选