Three-Lens Endoscope Objective with Cemented Element
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Solution Overview
Problem
Conventional endoscope objective lenses are bulky and have difficulty correcting chromatic aberrations effectively, which hinders their ability to accurately diagnose lesions and are not compact enough for reduced patient burden.
Innovation Solution
A compact objective lens configuration with three lenses, including a single negative lens, an aperture stop, and a cemented lens formed by a positive and negative lens, where the aperture stop is positioned between the single lens and the cemented lens, satisfying specific conditional formulae to balance chromatic aberrations and achieve favorable optical performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the number of lenses is decreased to make the endoscope thinner and more compact, then the device complexity and diameter are reduced, but the ability to correct chromatic aberrations deteriorates
Solution Approach 1:
The patent combines a positive lens and a negative lens into a single cemented lens unit. This merging allows the system to maintain only three lenses total while achieving effective chromatic aberration correction through the complementary optical properties of the cemented positive and negative lenses working together as one integrated element.
Solution Approach 2:
The patent applies different optical properties to different parts of the lens system by using a cemented lens where the positive lens and negative lens have different refractive indices and dispersion characteristics. This local differentiation of optical properties enables chromatic aberration correction within the constrained three-lens configuration.
2Ease of manufacture
If a non-cemented lens configuration is used, then the manufacturing process is simpler, but chromatic aberration correction becomes difficult
Solution Approach 1:
The cemented lens merges two lenses with different optical properties into a single physical unit. This combination provides chromatic aberration correction capability that would be difficult to achieve with separate lenses, while the cementing process itself is a standardized manufacturing technique that maintains ease of production.
3Device complexity
If the aperture stop is positioned at the object side of the lens, then the lens configuration is simplified, but chromatic aberrations cannot be balanced between object side and image side
Solution Approach 1:
The patent positions the aperture stop between the single negative lens and the cemented lens, creating asymmetric positioning that balances chromatic aberrations. This local optimization of aperture stop location allows different parts of the optical path to be corrected for chromatic effects, achieving balance between object side and image side while maintaining a relatively simple three-lens configuration.
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 results in a compact, high-performance objective lens that effectively corrects chromatic aberrations, enabling accurate lesion detection and reducing the burden on patients by allowing for thinner, more efficient endoscope designs with a wider field of view.
Implementation Method 1
the present disclosure provides an objective lens for endoscopes having a small number of lenses and a compact configuration, which corrects chromatic aberrations
Implementation Method 2
a cemented lens; the cemented lens being formed by one positive lens and one negative lens which are cemented together
Data Source
AI summary
The number of lenses within an objective lens for endoscopes is only three. The objective lens for endoscopes includes, in order from the object side, a first lens which is a single lens having a negative refractive power and a concave surface toward the object side, an aperture stop, and a cemented lens. The cemented lens is formed by cementing one positive lens and one negative lens together. Conditional formulae related to the distance from the surface toward the object side of the first lens to the aperture stop and the Abbe's numbers of the positive lens and the negative lens that constitute the cemented lens are satisfied.