Study Of Imaging Objective For Near-infrared Confocal Endomicroscopy

Cancer is a major disease that threatens human health,and early diagnosis can help achieve effective treatment.Fluorescence confocal endoscopy is now widely used in the clinical diagnosis of early cancer.Fiber-based fluorescence confocal endoscopy can be compatible with conventional endoscopy,which could get through the conventional endoscope working channel into the human body with the fiber bundle,achieving real-time high-resolution imaging.In recent years,near-infrared fluorescence imaging technology began to develop,which is very suitable for deep tissue imaging.Combined with indocyanine green fluorescent probe for confocal detection,it is a promising technology with low spontaneous fluorescence,high contrast,and better security in clinical.As an important component of the probe of fluorescence confocal endoscopy,micro-microscopic objective lens play an important role in imaging process.This paper designs a near-infrared micro-microscopic objective lens based on the requirements of the large field of view and deep imaging depth of near-infrared confocal endoscopy system.Firstly,this paper analyzes the requirements of the system,determining the characteristic parameters of the micro-microscopic objective lens.The performance analysis is performed with the design software ZEMAX.The structure of the lens and the lens barrel is optimized by combining the current processing technology,and then the fabrication of the micro-microscopic objective lens is completed.A micro-microscope objective with an outer diameter of 2.6 mm and an overall length of 8.75 mm was finally designed for a wavelength range of 785-860 nm,which has a working distance of 300 μm and a field of view of 340 μm.Secondly,the test system is built to test the micro-microscopic objective lens.The test results show that the micro-microscopic objective lens designed satisfies the requirement of near-infrared confocal endoscopic imaging.Thirdly,the method of coupling the micro-microscopic objective lens and the fiber bundles is described in order to create a complete imaging probe for near-infrared confocal endoscopy.Finally,the work of this paper is summarized,and the direction of the next stage of work is put forward.