Catadioptric Element Corrects Lateral Chromatic Aberration
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Solution Overview
Problem
Wide-angle optical systems, particularly in endoscopes, face challenges in correcting lateral chromatic aberration and aligning image directions across all fields of view effectively.
Innovation Solution
A wide-angle optical system comprising a first group with a negative lens and a positive lens, a second group with a catadioptric optical element, and a third group with positive refractive power, where the catadioptric optical element includes specific surfaces for light transmission and reflection, ensuring that all principal rays from both the front and lateral directions are refracted and reflected in a manner that allows for correction of lateral chromatic aberration by a single optical element.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a conventional optical system with multiple reflection surfaces is used, then the field angle can be widened, but lateral chromatic aberration cannot be sufficiently corrected
Solution Approach 1:
The optical system is divided into distinct functional groups: a first group with negative refractive power for light collection, a second group with positive refractive power for image formation, and a catadioptric optical element with dedicated reflection surfaces. This segmentation allows each component to be optimized for its specific function, enabling both wide field angle and aberration correction.
Solution Approach 2:
A catadioptric optical element is introduced as an intermediary component between the negative and positive lens groups. This element includes a first reflection surface and a second reflection surface that work together to redirect light paths and correct lateral chromatic aberration while maintaining the wide field angle capability.
2Manufacturing precision
If multiple optical elements are added to correct aberration, then lateral chromatic aberration can be corrected, but the device complexity increases
Solution Approach 1:
The catadioptric optical element merges reflection and refraction functions into a single integrated component. By combining a first reflection surface, a second reflection surface, and transmission surfaces in one element, the system achieves aberration correction without adding multiple separate optical components, thus controlling device complexity.
Solution Approach 2:
The catadioptric optical element performs multiple functions simultaneously: it reflects light from the first reflection surface, reflects light from the second reflection surface, and transmits light through transmission surfaces. This multi-functionality allows a single element to correct lateral chromatic aberration while maintaining the wide field angle, reducing the need for additional specialized components.
3Device complexity
If the optical system is simplified to reduce complexity, then device complexity decreases, but image direction alignment across fields of view deteriorates
Solution Approach 1:
The catadioptric optical element employs asymmetric surface configurations with specific curvature radii and positions. The first reflection surface, second reflection surface, and transmission surfaces are designed with different geometric parameters to independently control light paths from different fields of view, enabling precise image direction alignment without requiring symmetric or overly complex arrangements.
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 effectively corrects lateral chromatic aberration and aligns image directions in all fields of view, enhancing the quality of wide-angle imaging in endoscopes.
Implementation Method 1
a first reflection surface that is disposed in a ring shape around the first transmission surface and that reflects light from the image side
Implementation Method 2
a second reflection surface that is disposed in a ring shape around the second transmission surface and that reflects light from the object side
Implementation Method 3
a first group having a negative lens with negative refractive power
Implementation Method 4
a positive lens with positive refractive power
Data Source
AI summary
A wide-angle optical system includes a first group having negative and positive lenses, a second group having a catadioptric optical element, and a third group. The catadioptric optical element includes a first surface at an object side, a second surface at an image side, and a third surface. The first surface has a first transmission surface and a first reflection surface disposed therearound. The second surface has a second transmission surface and a second reflection surface disposed therearound. The third surface is a circular conical transmission surface that is disposed between the first surface and the second surface and an apex of which is located at the object side.