and the main one is called endoscopy.

一种主要的方法称为内窥镜法
Endoscopy involves objects called fiber optics,

内窥镜要利用光纤这种东西
and fiber optics allow you to not only focus light through a lens

而光纤不仅能将光线集中镜头处
but to take that light and bounce it down an optical shaft.

还能令光线只在纤维内部传播
I could take a light beam and shine it here into a fiber.

我可以用一束光线照进纤维内部
That fiber has a special coating on which then allows

这种纤维表面包覆着一种特殊的物质
the light to bounce all the way down the fiber.

能够将光线反射的路径集中在纤维内部
I can bend the fiber,

我可以弯折这根纤维
and because the bouncing depends on the coating

因为光线反弹的界面是包覆物
and not the shape of the fiber,

而不是纤维的形状
the light will turn with the fiber.

光线会随着光纤的转动而改变方向
This is how fiber optics works;

这是光纤的工作原理