请问这句话是什么意思？

Note that the basic laser system is with laser head and collimating optics mounted on rail with enclosure.

Optical Enclosure
The laser heads are contained in an enclosure consisting of a tooling plate base and a hinged, interlocked cover.  An air filtration system provides a clean, positive pressure, environment for the optics, to protect against environmental dust.

The enclosure also includes optics to couple into the optical fiber, and a combination beam dump shutter/absolute power meter.

这几句话中都有enclosure，enclosure在这几句话中分别是什么意思？ 谢谢！

http://www.minitecframing.com/ap ... nclosures/index.htm

Note that the basic laser system is with laser head and collimating optics mounted on rail with enclosure.
（需要注意的是：这个基本的激光系统是由激光头和安装在导轨上的准直光学系统组成，并且该系统是密闭的）
Optical Enclosure
（光学密封）
The laser heads are contained in an enclosure consisting of a tooling plate base and a hinged, interlocked cover.  An air filtration system provides a clean, positive pressure, environment for the optics, to protect against environmental dust.
（很多激光头装在一个箱子里面，而该箱子由可以固定其它器件的基板、合页、带锁的盖子构成。一个空气过滤系统给光学系统提供清洁、正的气压环境以防止带有灰尘的环境的影响）
The enclosure also includes optics to couple into the optical fiber, and a combination beam dump shutter/absolute power meter.
（这个密封结构也包括将光耦合进光纤的光学系统，并且也包括一个合束装置，该合束装置用于关闭/绝对光功率的对比分析测量）
不妥之处请坛友批评指正，仅供参考哦，呵呵