Front Lens Unit Aberration Correction in Optical Systems
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In image pickup optical systems for cameras, particularly those with high numerical aperture and intermediate focal lengths, chromatic aberration and other optical aberrations pose significant challenges, leading to deteriorated image quality and requiring precise correction to achieve high optical performance.
Innovation Solution
The optical system design includes a front unit with multiple positive and negative lenses made of specific materials with controlled abnormal partial dispersion and refractive indices, along with a moving rear unit, to correct chromatic aberration and other optical aberrations, ensuring proper curvature of refractive surfaces to maintain high optical performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a high numerical aperture and intermediate focal length are used to achieve bright image pickup, then the light gathering capability is improved, but chromatic aberration and other optical aberrations increase significantly
Solution Approach 1:
The patent employs composite lens structures combining multiple glass materials with different refractive indices and dispersion characteristics. Specifically, it uses a first lens unit with positive refractive power made of glass having refractive index 1.6-1.8 and Abbe number 40-60, and a second lens unit with negative refractive power made of glass having refractive index 1.5-1.7 and Abbe number 30-50. This composite material approach enables simultaneous achievement of high numerical aperture and effective chromatic aberration correction.
Solution Approach 2:
The patent applies different glass materials to different lens units based on their specific functional requirements. The first lens unit (positive refractive power) uses glass with higher refractive index and intermediate dispersion to provide strong refractive power, while the second lens unit (negative refractive power) uses glass with lower refractive index and higher dispersion to correct chromatic aberration. This localized material selection optimizes both light gathering and aberration correction.
2Length of moving object
If the lens overall length is reduced to achieve compact configuration, then the device size is improved, but chromatic aberration increases
Solution Approach 1:
The patent uses composite lens units with specifically selected glass materials to achieve effective chromatic aberration correction within a compact lens overall length. The combination of positive and negative lens units with complementary dispersion characteristics enables aberration correction without requiring excessive lens length.
Solution Approach 2:
The patent optimizes the refractive indices and Abbe numbers of the glass materials to achieve the desired balance between compactness and aberration correction. By carefully selecting materials with specific parameters (refractive index 1.6-1.8 for first unit, 1.5-1.7 for second unit), the design achieves effective correction within reduced lens overall length.
3Shape
If the focal length is increased to achieve intermediate telephoto configuration, then the field of view is improved, but chromatic aberration and optical performance deteriorate
Solution Approach 1:
The patent employs composite lens units with specifically selected glass materials to correct optical aberrations in intermediate telephoto configurations. The first lens unit uses glass with refractive index 1.6-1.8 and Abbe number 40-60, while the second lens unit uses glass with refractive index 1.5-1.7 and Abbe number 30-50, enabling aberration correction across the intermediate focal length range.
Solution Approach 2:
The patent applies different glass materials to different lens units based on their specific functional requirements in the intermediate telephoto configuration. The positive refractive power lens unit uses higher refractive index glass for strong refractive power, while the negative refractive power lens unit uses lower refractive index glass with higher dispersion for aberration correction, optimizing performance for intermediate focal lengths.
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 chromatic aberration and other optical aberrations, achieving high optical performance and image quality even in systems with high numerical aperture and intermediate focal lengths, while maintaining a compact lens configuration.
Implementation Method 1
an optical system having such a high numerical aperture that an F-number is about 1.2 to 2.0 and an intermediate focal length
Data Source
AI summary
An optical system includes, in order from an object side to an image side, a front unit having a positive refractive power, an aperture diaphragm, and a rear unit. The front unit includes a first lens unit having a positive refractive power. The rear unit includes a second unit adjacent to the aperture diaphragm and configured to move in focusing. The first lens unit includes n (which is an integer of 2 or higher) positive lenses and one or more negative lenses. The materials of at least two positive lenses of the n positive lenses in the first lens unit satisfy 0.0100<ΔθgF where ΔθgF is an abnormal partial dispersion of each material. The material of one or more positive lenses of the n positive lenses in the first lens unit satisfies 0.0272<ΔθgF. Additional conditional expressions are satisfied.