The hard tube endoscope is mainly composed of an optical imaging system
and an illumination system: the optical part looks like a slender metal
tube, and inside is a complete optical system composed of many lenses.
The optical imaging system consists of three major systems: the
objective lens system, the image relay system, and the eyepiece system.
The inverted image of the object to be observed is formed by the
objective lens, and the inverted image is converted into a positive
image by the relay system, and transmitted to the eyepiece, and then
magnified by the eyepiece, and then observed by the human eye. In order
to form different viewing angles, different prisms need to be added.
Endoscopes for different purposes are made into different shapes, outer
diameters and lengths according to the requirements of use to meet the
requirements of use. The illumination transmission system is composed of
optical fiber, which transmits the light of the cold light source to
the front end of the endoscope through the optical fiber to illuminate
the observed object.