Endoscope Objective Optical System with Movable Lens Group
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Solution Overview
Problem
Current endoscope optical systems face challenges in providing both magnified and wide-angle observations necessary for otorhinolaryngology and craniocervical surgery, particularly in detecting precancerous lesions, due to the need for high magnification and wide-angle views of capillary blood vessels without causing tissue injury.
Innovation Solution
An endoscope objective optical system comprising a first lens group with positive refractive power, a second lens group with negative refractive power, and a third lens group with positive refractive power, where the second lens group moves along the optical axis, and specific conditional expressions are satisfied to ensure optimal focal lengths and thickness ratios, allowing for both magnified and normal observations with improved imaging performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a magnifying optical system with high magnification is used to observe capillary blood vessels, then the observation precision is improved, but the observation range becomes narrow
Solution Approach 1:
The optical system employs a movable second lens group that can be positioned at different locations along the optical axis. When the second lens group is at a first location, the system provides magnified observation with high precision for capillary blood vessels. When the second lens group is at a second location, the system provides wide-angle observation with a broader observation range. This dynamic repositioning of the second lens group allows the system to adapt between magnified and wide-angle observation modes, resolving the contradiction between observation precision and observation range.
2Area of stationary object
If an optical system with wide angle is used to observe a wide range, then the observation range is improved, but the magnification capability is reduced
Solution Approach 1:
The optical system uses the movable second lens group to dynamically adjust between wide-angle and magnified observation modes. When the second lens group is positioned at the second location, the system achieves wide-angle observation with a broad observation range suitable for determining insertion portion steering direction. When the second lens group is positioned at the first location, the system achieves high magnification capability for detailed observation of capillary blood vessels. This dynamic configuration resolves the contradiction between observation range and magnification capability.
3Measurement precision
If the second lens group is designed with specific focal length and thickness ratios, then the imaging performance is improved, but the device complexity increases
Solution Approach 1:
The optical system optimizes the focal length of the second lens group (f2) and its thickness (Σd2) to satisfy specific conditional expressions: -2.12 < f2/fW and 0.452 < Σd2/D2. By carefully controlling these parameters, the system achieves excellent imaging performance in both magnified and wide-angle observation modes. The conditional expressions ensure that the second lens group can effectively switch between observation modes while correcting optical aberrations. This parameter optimization approach improves imaging performance while keeping the device complexity manageable through precise mathematical constraints rather than complex mechanical structures.
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 system enables effective magnified observation of capillary blood vessels while maintaining a wide observation range, ensuring precise detection of precancerous lesions and minimizing tissue injury, with a compact and lightweight design that simplifies the drive mechanism.
Implementation Method 1
a first lens group having a positive refractive power, a second lens group having a negative refractive power, and a third lens group having a positive refractive power, wherein a lens surface positioned nearest to an image side in the second lens group is a concave surface which is directed toward the image side, the second lens group moves along an optical axis
Data Source
AI summary
The endoscope objective optical system includes in order from an object side, a first lens group having a positive refractive power, a second lens group having a negative refractive power, and a third lens group having a positive refractive power. A lens surface positioned nearest to an image side in the second lens group is a concave surface which is directed toward the image side. The second lens group moves along an optical axis.