Imaging Optical System Aberration Correction via Cemented Lens Groups
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Solution Overview
Problem
Current imaging devices face challenges in achieving high performance with a wide angle of view while maintaining compactness, as they struggle to correct coma, distortion, and chromatic aberrations, especially when the size of the image sensor increases, requiring a balance between lens diameter and optical system length.
Innovation Solution
The proposed imaging optical system includes a specific arrangement of lenses with negative and positive refractive powers, including cemented lens groups, an aperture stop, and a meniscus lens, optimized with conditional expressions to correct aberrations and reduce the overall size of the device, ensuring a half angle of view of 35 degrees or more and an F number of 2.8 to 3.3.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the size of the image sensor is increased to achieve high resolution, then the imaging performance is improved, but the total length of the image-forming lens system must be significantly reduced to maintain compactness
Solution Approach 1:
The lens system is divided into multiple lens groups (first through sixth lenses) with alternating positive and negative refractive powers. Each lens group performs specific optical functions, allowing the system to achieve high resolution on large sensors while maintaining a compact overall length through distributed optical power management.
Solution Approach 2:
The patent employs a cemented lens structure where the second lens (negative) and third lens (positive) are joined together to form a cemented lens group. This composite structure enables precise control of chromatic aberration and other optical parameters, achieving high imaging performance within a compact form factor.
2Measurement precision
If the F number is reduced to 2.8-3.3 to increase lens diameter for high performance, then the imaging quality is improved, but the lens diameter increases which conflicts with compactness requirements
Solution Approach 1:
The patent optimizes the F number to a specific range of 2.8-3.3, balancing aperture size for light gathering capability with overall system compactness. The conditional expressions define precise parameter ranges for lens curvatures, distances, and powers that enable achieving high imaging quality without excessive lens diameter increase.
3Adaptability or versatility
If a retrofocus configuration with negative lens group on object side and positive lens group on image side is used to achieve wide angle of view, then the half angle of view reaches 35 degrees or more, but the system complexity increases
Solution Approach 1:
The patent employs a retrofocus configuration where the first lens has negative refractive power and the fourth lens has positive refractive power, creating a dynamic optical path that enables wide angle of view (35 degrees or more). The conditional expressions optimize the distribution of refractive powers to achieve wide viewing angles while controlling system complexity through mathematical relationships between lens parameters.
4Reliability
If multiple lens groups with alternating positive and negative refractive powers are arranged to correct aberrations, then coma and chromatic aberrations are reduced, but the manufacturing precision requirements increase
Solution Approach 1:
The cemented lens structure combining the second negative lens and third positive lens into a single unit provides inherent alignment precision and stable optical performance. This composite approach reduces manufacturing complexity compared to separate mounted elements while effectively correcting chromatic aberration through the controlled refractive index difference between cemented materials.
Solution Approach 2:
The patent defines specific conditional expressions for lens curvatures, distances, and refractive powers that optimize aberration correction while considering manufacturing feasibility. These parameter relationships ensure that the alternating positive-negative lens groups work together effectively without requiring excessive manufacturing precision beyond standard capabilities.
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 coma aberration, achieving a compact and high-performance imaging system with improved portability and image quality, while maintaining the necessary refractive power balance to prevent lens diameter increase.
Implementation Method 1
a first lens L1 having negative refractive power, a second lens L2 having negative refractive power, a third lens L3 having positive refractive power, an aperture stop S, a fourth lens L4 having positive refractive power, a fifth lens L5 having negative refractive power, and a sixth lens L6 arranged in that order from the object side
Data Source
AI summary
An imaging optical system including a first lens having negative refractive power; a second lens having negative refractive power; a third lens having positive refractive power; an aperture stop; a fourth lens having positive refractive power; a fifth lens having negative refractive power; and a six lens arranged in that order from an object side. The first lens is a negative lens with a concave surface facing the image side. The second lens is a negative lens with a concave surface facing the object side. The second lens and the third lens are joined together to form a cemented lens have positive refractive power.