An endoscope is composed of a tube (or insertion tube), a lens (or image beam), an illumination fiber, a mirror body (or body), and other parts.
Endoscopy is used to observe the internal body cavity of the human body, through which the composition and morphology of internal organs can be directly observed. Endoscopy has become an indispensable and reliable tool for medical diagnosis and minimally invasive surgery
Although there are various types of hard tube endoscopes, their basic structure is consistent. The internal optical system is composed of a series of lenses, whose function is to image the observed object to the observer through the optical system
On the retina.
The optical system of a rigid tube endoscope usually consists of three parts: an objective lens (including a prism), a rod lens, and an eyepiece.
Objective lens system:
Objective lenses are usually composed of 2-4 lenses (glued lenses). The main function of an objective lens is to image an object in front of the lens. If the viewing angle is not 0 ° (direct view), such as squint, lateral view
A visual endoscope requires the placement of a prism for image transformation within the objective lens group.
Composed of multiple sets of identical sized image conversion lenses. The main function of a rod mirror is to transmit the image formed on the objective lens to the light source position. According to the working length of the endoscope, there are 1, 3, 5, and 7 sets of rotating rods
Composed of lenses, the number of rod mirrors in the image conversion system is usually odd.
The eyepiece is located inside the square mirror behind the endoscope. The main function of an eyepiece is to magnify the image formed by the light source, and the magnification of the eyepiece is generally between 15 and 30. The magnification should not be too large, otherwise the object image
Will not be able to see clearly.
The insertion part of the hard tube endoscope is composed of an outer tube, an inner tube, and an illumination fiber. The lighting fiber is located between the inner tube and the outer tube to illuminate the entire field of view.
Internal structure of hard tube endoscopy