Endoscope Illumination Lens Internalizing Convergence Points
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Solution Overview
Problem
Existing endoscope illumination optical systems face challenges in achieving wide-angle light distribution while maintaining low-invasive illumination, as convergence points of light can be misplaced due to manufacturing tolerances, leading to potential light invasion and uneven illumination.
Innovation Solution
An illumination lens system comprising two lenses with specific geometric and refractive index conditions, where the first lens has a convex incident surface and the second lens has a flat emission surface, ensuring that light convergence points are internalized to prevent light invasion and provide a wide-angle illumination, with focal length and refractive index ratios optimized to maintain low-invasive and uniform light distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a condenser lens consisting of two lenses is used to achieve wide-angle illumination, then the illumination angle is widened, but the convergence point of light may be positioned close to the object to be observed, causing light invasion
Solution Approach 1:
The patent applies parameter changes by optimizing the focal lengths of the first and second lenses (satisfying 0.61 < f/f1 < 1.0 and 0.4 < f/f2 < 0.8), the refractive indices of the lens materials (1.8 < Nd1 < 2.0 and 1.8 < Nd2 < 2.0), and the thickness of the second lens (0.05 < t < 0.15) to control the convergence point position and achieve wide-angle illumination without light invasion
Solution Approach 2:
The patent controls the spatial distribution of light convergence by positioning the intersection of specific rays (at heights 0.25×H and 0.5×H from the optical axis) within the illumination lens itself, using dimensional constraints on ray intersection positions to prevent light invasion while maintaining wide illumination angle
2Device complexity
If the convergence point position is not clearly specified or is positioned inside the lens system, then the lens design is simpler, but manufacturing tolerance variations can shift the convergence point outside the lens, causing light invasion
Solution Approach 1:
The patent incorporates manufacturing tolerance compensation by designing the lens parameters with sufficient margins (e.g., t > 0.05 ensures the second lens is thick enough to accommodate variations), so that even with manufacturing variations, the convergence point remains positioned within the illumination lens and light invasion is prevented
Solution Approach 2:
The patent optimizes specific parameter ranges (focal length ratios, refractive indices, lens thickness) to create a robust design where the convergence point position is stable against manufacturing variations, balancing design simplicity with reliability
3Illumination intensity
If high energy is generated at the convergence point of light, then the illumination intensity is high, but the light may invade the object to be observed, increasing patient burden
Solution Approach 1:
The patent applies local quality by controlling the spatial distribution of light energy - the convergence point is positioned within the illumination lens where it can be contained, while the emission surface provides wide-angle diffuse illumination to the observation area, achieving high illumination intensity where needed without concentrating high energy at the object location
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 wide-angle illumination with low-invasive light distribution, reducing the risk of light invasion and ensuring robustness against manufacturing variations, while allowing for easy cleaning and minimizing light density outside the lens, thus enhancing the illumination optical system's performance.
Implementation Method 1
The illumination lens consists of two lenses consisting of a first lens and a second lens arranged in this order toward an object side from a light source side... an incident surface of the first lens on which light generated from a light source is to be incident is a convex surface, and an emission surface of the second lens from which light toward an object is to be emitted is a flat surface
Data Source
AI summary
An illumination lens consists of two lenses consisting of a first lens and a second lens arranged in this order from a light source side, and surfaces of all the lenses have a planar shape or a convexly spherical shape. An incident surface of the first lens is a convex surface, and an emission surface of the second lens is a flat surface. An intersection of a ray incident in parallel to an optical axis at a height of 0.25×H and a ray incident in parallel to the optical axis at a height of 0.5×H is positioned only inside the illumination lens in a case in which an outer diameter of the first lens is denoted by 2H. Predetermined Conditional Expression related to a focal length of the illumination lens and a focal length of the first lens is satisfied.