Optical System Layout for Compact Aberration-Corrected Imaging
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Solution Overview
Problem
Existing optical systems in cameras face challenges in achieving a balance between size, weight, and optical performance, particularly in correcting aberrations while maintaining favorable imaging quality.
Innovation Solution
The optical system is designed with specific conditional expressions to include a first lens group with positive refractive power, a focusing group that moves along the optical axis, and a rear group, with lenses arranged to satisfy conditions such as FNo×(TL/f)^2 < 2.5 and dA/dG1 < 0.8, ensuring a compact and lightweight design while correcting aberrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the optical system uses more lenses and larger aperture to improve imaging quality and aberration correction, then the optical performance is improved, but the size and weight of the system increases
Solution Approach 1:
The patent applies parameter changes by precisely controlling the ratio of air space to first lens group length (dA/dG1) and the f-number (FNo) to achieve optimal imaging quality with minimized system weight. By setting specific parameter ranges rather than simply adding more lenses, the system achieves high performance without excessive weight increase
Solution Approach 2:
The optical system is segmented into distinct functional groups: the first lens group with positive refractive power for light gathering, the focusing group for focus control, and the rear group for aberration correction. This segmentation allows each group to be optimized independently, achieving high imaging quality without requiring a monolithic large-aperture design that would increase overall weight
2Reliability
If the optical system uses more lenses and larger aperture to improve aberration correction, then the optical performance is improved, but the overall system size increases
Solution Approach 1:
The patent uses parameter changes by establishing specific relationships between the air space length (dA), first lens group length (dG1), and system parameters (FNo, TL, f). By controlling the ratio dA/dG1 within a specific range and setting constraints on FNo×(TL/f)^2, the system achieves effective aberration correction while maintaining a compact overall length
Solution Approach 2:
The first lens group with positive refractive power acts as an intermediary element that enables effective aberration correction by the rear group without requiring increased system length. The focusing group serves as another intermediary that allows focus adjustment without expanding the overall system dimensions
3Weight of stationary object
If the optical system reduces size and weight by using fewer lenses, then the portability is improved, but the ability to correct aberrations deteriorates
Solution Approach 1:
The patent achieves aberration correction with reduced weight by changing the parameters of existing lens groups rather than simply reducing their number. By optimizing the ratio dA/dG1 and controlling the f-number FNo, the system maintains effective aberration correction capability while using fewer and lighter lens elements
Solution Approach 2:
The first lens group with positive refractive power serves multiple functions: light gathering, initial aberration control, and enabling the rear group to correct remaining aberrations efficiently. The focusing group also serves dual purposes of focus adjustment and contributing to overall aberration correction, reducing the need for additional dedicated correction lenses
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 system achieves a small and lightweight configuration with improved imaging performance by optimizing lens arrangements and aberration correction, meeting the desired optical performance criteria.
Implementation Method 1
a first lens group having positive refractive power
Implementation Method 2
a focusing group that moves along an optical axis at focusing
Data Source
AI summary
An optical system used in an optical apparatus is configured to include a first lens group having positive refractive power, a focusing group that moves along an optical axis at focusing, and a rear group, in order from an object side, so that the first lens group includes a first-A lens group disposed on the object side of the largest air space A in the first lens group, and that all of the following conditional expressions are satisfied:1.<FNo×(TL/f)2<2.5 and 0.3<dA/dG1<0.85where FNo is the f-number of the optical system focusing on infinity, TL is the total optical length of the optical system focusing on infinity, f is the focal length of the optical system focusing on infinity, dA is the length on the optical axis of the air space A, and dG1 is the length on the optical axis of the first lens group.