The polycarbonate itself is part of the optical system for reading the pits.
聚碳酸脂本身是用于读取坑形的光学系统的一部分。
2
Lena unit, lens, optical device, image reading unit, scanner and image forming device.
透镜单元，镜筒，光学装置，图像读取单元，扫描仪和图像形成设备。
3
A digitized ruler with absolute code is adopted as the reference of the system, and the ruler is read by the reading system which is composed of optical system, CCD camera and computer.