Wide Angle Lens Aberration Correction Ghost Reduction
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Solution Overview
Problem
Conventional wide angle lenses suffer from poor optical performance and are prone to generating ghosts and flares due to reflected light, which affects their aberration correction and overall imaging quality.
Innovation Solution
The optical system comprises a first lens group with negative refractive power and a second lens group with positive refractive power, where the second lens group moves upon focusing, with specific focal length ratios and configurations that include aspherical lenses and antireflection coatings to minimize aberrations and reflections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional wide angle lens design is used, then the lens structure is simple, but optical performance is poor and ghosts and flares are easily generated
Solution Approach 1:
The lens is divided into multiple lens groups (first lens group with negative refractive power, second lens group with positive refractive power) where the second lens group can move independently for focusing. This segmentation allows complex aberration correction to be achieved through coordinated movement of specific groups rather than requiring complex individual lens elements throughout the entire lens structure.
Solution Approach 2:
The second lens group is designed to move along the optical axis when focusing from infinity to finite distances, while the first lens group remains fixed. This dynamic configuration enables the lens to correct aberrations and control ghost/flare by adjusting the relative positions of lens groups during focusing operations, improving optical performance without proportionally increasing structural complexity.
2Manufacturing precision
If the lens focuses from infinity to finite distance with a fixed structure, then manufacturing is easier, but aberration correction performance deteriorates
Solution Approach 1:
By making only the second lens group movable while keeping the first lens group fixed, the design achieves dynamic aberration correction capability. This selective movement approach maintains manufacturing simplicity compared to making the entire lens movable, while still providing the necessary focus adjustment range from infinity to finite distances with improved aberration control.
3Object-affected harmful factors
If multilayer film design is used to improve antireflection coating performance, then ghosts and flares are reduced, but manufacturing complexity increases
Solution Approach 1:
The patent employs an antireflection coating with a specific two-layer structure where the first layer has refractive index 1.30 or less and the second layer has refractive index 1.40 or more. This composite coating structure effectively suppresses reflected light and reduces ghosts and flares by utilizing the different refractive indices to cancel reflections at multiple wavelengths, achieving superior antireflection performance through material composition rather than complex multi-layer designs.
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 enhances optical performance by reducing ghosts and flares, improving aberration correction, and enabling a more compact lens design with better image forming capabilities.
Implementation Method 1
a first lens group having negative refractive power; and a second lens group having positive refractive power
Implementation Method 2
the rear group of the second lens group has at least one aspherical lens
Implementation Method 3
an antireflection coating which is performed on a lens surface
Implementation Method 4
multilayer film design technology and multilayer film forming technology
Data Source
AI summary
An optical system WL has, in order from an object, a first lens group G1 having negative refractive power and a second lens group G2 having positive refractive power, wherein the first lens group G1 is fixed and the second lens group G2 moves upon focusing from an object at infinity to an object at a finite distance, and the second lens group G2 is formed of a front group G2a located closer to the object than an aperture stop S disposed in the second lens group G2, and a rear group G2b located closer to an image than the aperture stop S.