Condensing Optical System for Compact Confocal Endoscope
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Solution Overview
Problem
Existing confocal optical systems for endoscopes face challenges in miniaturizing the flexible tube while maintaining high image resolution and reducing light loss and aberrations, particularly when using a swinging point source for scanning, as previous designs require large objective lenses and suffer from inefficient light usage and inaccurate focal positioning.
Innovation Solution
A condensing optical system is designed with specific configurations, including a first group with positive power, a deflecting group, and a second group with positive power, optimized to satisfy conditions such as |m×NA| < 0.2, with a point source moved orthogonally to the optical axis, and a cover glass to adjust the focal position, minimizing light loss and aberrations, and allowing for a wide scan range within a compact size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If the distance between the light source and the objective lens is set long to secure space for reflecting surfaces, then the optical path length is sufficient, but the diameter of the objective lens must be large and scan range becomes limited
Solution Approach 1:
The patent places the reflecting surface inside the objective lens structure, specifically on the rear surface of the lens, rather than requiring external space. This nested configuration allows the optical path to be folded within the lens assembly itself, achieving sufficient optical path length without increasing the external diameter of the objective lens.
Solution Approach 2:
The patent utilizes the depth dimension (optical axis direction) by positioning the reflecting surface at the rear of the objective lens, effectively using the internal space along the optical path rather than expanding the lateral dimensions. This allows compact configuration while maintaining adequate optical path length.
2Length of stationary object
If reflecting surfaces are used to scan the beam, then the optical path length is secured, but light quantity is lost on each reflection and beam efficiency decreases
Solution Approach 1:
The patent changes the optical parameters by using a lens-based confocal system where the objective lens itself focuses the beam, eliminating the need for additional reflecting surfaces for beam scanning. This reduces the number of reflections and associated light losses while maintaining the required optical path length through proper lens positioning and design.
3Area of stationary object
If the optical system is miniaturized to reduce flexible tube diameter, then the endoscope becomes more usable, but the scan range and image quality deteriorate
Solution Approach 1:
The patent integrates the confocal optical system within the flexible tube by nesting the reflecting surface inside the objective lens structure and positioning components紧凑ly along the optical axis. This allows the confocal observation function to be incorporated without significantly increasing the external diameter of the flexible tube.
Solution Approach 2:
The patent combines the confocal observation optical system with the flexible tube structure, integrating multiple functions (illumination, observation, and confocal scanning) into a unified compact system. This merging allows the system to maintain small diameter while preserving essential scan capabilities through efficient use of internal space.
4Area of stationary object
If the optical system is miniaturized to reduce flexible tube diameter, then the endoscope becomes more usable, but image resolution and definition decrease
Solution Approach 1:
The patent optimizes optical parameters including the numerical aperture (NA) of the objective lens, the position of the confocal pinhole, and the focal length relationships to maintain high image resolution within the miniaturized system. By carefully controlling these parameters, the system achieves confocal observation quality despite the reduced size of the flexible tube.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution enables the creation of a compact confocal optical system that reduces light loss and aberrations, allowing for high-definition, wide-range scanning and tomogram observation with a minimized flexible tube diameter, enhancing the usability of integrated endoscopes by reducing operator load.
Implementation Method 1
a condensing optical system for condensing a beam emitted from the point source
Implementation Method 2
a deflecting group, and a second group with positive power... scans a beam spot on the subject surface by swinging the point source of light
Data Source
AI summary
A condensing optical system, suitable for a scanning confocal optical system (having a composition for scanning a beam spot on a subject surface by swinging a point source of light) and capable of satisfactorily suppressing various aberrations and reducing loss of light quantity, is provided. The condensing optical system, installed in a scanning confocal optical system for obtaining images of a subject surface by scanning a beam emitted from a point source of light by moving the point source which serves as a pinhole for confocal observation, is configured to satisfy the following condition0.1<|m×NA|<0.2where “m” denotes magnification of the condensing optical system and “NA” denotes a numerical aperture of the condensing optical system on its subject surface side.