An objective lens for an electronic endoscope

Abstract

An objective lens for an electronic endoscope includes: a first lens group, a diaphragm and a second lens group arranged in sequence along a straight line optical axis; the first lens group includes a first negative lens and a first cemented lens which are arranged successively from the object side along the straight line optical axis; the first cemented lens is formed by cementing a first positive lens and a second negative lens; the second lens group includes a second positive lens and a second cemented lens which are arranged successively from the object side along the straight line optical axis; the second cemented lens is formed by cementing a third negative lens and a third positive lens; the cementing surface of the first cemented lens and the cementing surface of the second cemented lens face the direction opposite to the diaphragm; the objective lens for an electronic endoscope meets the first condition that Vp-Vn is not less than 30, wherein Vp is the abbe number of the third positive lens and Vn is the abbe number of the third negative lens. The objective lens for an electronic endoscope can expand a field angle.

Description

technical field [0001] The invention relates to the technical field of electronic endoscopes, in particular to an objective lens for electronic endoscopes. Background technique [0002] Electronic endoscope is a medical electronic optical instrument that can be inserted into the human body cavity and organ cavity for direct observation, diagnosis or treatment. It is widely used in various fields of clinical medicine, especially in the diagnosis of digestive tract diseases. substitute role. The larger the field of view angle observed by the electronic endoscope, the higher the image resolution, the more information the doctor can obtain, the higher the accuracy of disease diagnosis, and the shorter the diagnosis time. Therefore, the objective lens for electronic endoscope has the advantages of Wide angle and high resolution are necessary. [0003] The field angle of the existing objective lens for electronic endoscope is about 140°, and the image sensor used in conjunction ...

AI Technical Summary

Problems solved by technology

For example, when observing the wall or back side of the folds of the large intestine, this level of field of view requires the tip of the endoscope to be turned over at a large angle to achieve the required direction of observation. If the diameter of the lumen is small, the endoscope The movement of the tip part of the endoscope will be limited. In addition, changing the direction of the tip part of the endoscope too much will increase the complexity of the operation and the diagnosis time, thereby increasing the burden on the operator and the patient.

Images