Endoscopes have a series of high-resolution optical glass rod lenses. The endoscopes can be forward viewing (0 degrees) or angled (10–120 degrees) to allow visualization out of the axis of the telescope and increase the FOV by rotating the instrument. Under the condition of high refractive index, some optical components can achieve short focal length. Therefore, the micro lens becomes an ideal choice in the field of high precision applications. Because of the ultra-small size of this kind of lens(outer diameter 0.5mm-5mm, length: 0.5mm-30mm), either in spherical/round or rod shape, micro lens or ultra-small lens often requires special processing technology, unique production know-how and special optical fixture, etc.
