Endoscope Objective Lens Wide Angle View Design
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Solution Overview
Problem
Conventional endoscopes face challenges in achieving a wide angle of view while maintaining compact size and suitable optical performance, leading to restricted motion and increased diagnosis time due to issues like chromatic aberration and image quality deterioration.
Innovation Solution
The design incorporates a first lens group with a negative power and a second lens group with positive power, arranged in a specific configuration, along with conditions for focal lengths and radii of curvature to optimize the objective lens for a wide angle of view without compromising optical performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the angle of view is widened to increase observation field, then the observation field is increased, but the curvature of field increases and image quality deteriorates
Solution Approach 1:
The objective lens is divided into multiple lens groups (first lens group with negative power, second lens group with positive power, and third lens group) with specific focal length ratios. This segmentation allows each group to contribute differently to the overall optical performance, enabling wide angle of view while controlling field curvature through the coordinated action of divergent and convergent lens groups.
Solution Approach 2:
The patent applies specific parameter constraints including the focal length ratio condition (0.3 < ff/f < 0.6) and the radius of curvature condition for the negative front group lens ((R1+R2)/(R1-R2) between 1.2-2.0). These parameter optimizations enable the lens to achieve wide angle of view while maintaining image quality by controlling the magnitude of field curvature through precise mathematical relationships between lens parameters.
2Area of stationary object
If a high refractive index lens is used to widen the angle of view while maintaining compact size, then the angle of view is widened, but chromatic aberration of magnification occurs and image quality deteriorates
Solution Approach 1:
The patent employs a composite lens structure combining multiple lens groups with different refractive indices and optical powers. The first lens group (negative power) and second lens group (positive power) work together as an optical composite system that achieves wide angle of view while the diverse refractive index distribution across lens groups corrects chromatic aberration of magnification, maintaining image quality.
3Adaptability or versatility
If the tip portion is bent and turned to achieve desired observation direction with 140° angle of view, then the observation direction is adjusted, but the motion is restricted in small diameter tube cavities and diagnosis time increases
Solution Approach 1:
The patent achieves a wide angle of view of 170° or more through optimized optical parameters including the focal length ratio (0.3 < ff/f < 0.6) and specific lens curvature relationships. This increased angle of view reduces the need for tip portion manipulation, allowing operators to observe tube cavities more efficiently without excessive bending and turning, thereby reducing diagnosis time and improving ease of operation.
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
This configuration allows for a wider angle of view while maintaining high resolution and reducing chromatic aberration, enabling effective observation of tube cavities without sacrificing image quality or increasing the outer lens diameter.
Implementation Method 1
The objective lens comprises a first lens group having a negative power, an aperture stop, and a second lens group having a positive power. The first lens group includes a negative front group lens and a positive front group lens. The second lens group includes a positive rear group lens and a cemented lens.
Data Source
Figure 1~2
Figure 3(a)~4
Figure 5(a)~6
AI summary
An objective lens for an endoscope, comprising a first lens group having a negative power, an aperture stop, and a second lens group having a positive power arranged in this order from an object side, wherein the first lens group comprises at least a negative front group lens having a concave surface facing an image side, and a positive front group lens having a convex surface facing the image side arranged in this order from the object side, and the second lens group comprises at least a positive rear group lens having a convex surface facing the image side and a cemented lens formed by cementing together a negative lens and a positive lens being arranged in this order from the object side, and wherein the objective lens for an endoscope is configured to satisfy a predetermined condition.