Multi-unit Optical System Autofocus Aberration Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Optical systems for image pickup apparatuses face challenges in achieving a wide angle of view, large aperture ratio, and high-speed autofocus while maintaining compact size and correcting aberrations, especially when the focus lens unit is made lightweight for high-speed autofocus.
Innovation Solution
The optical system consists of multiple lens units, where the first, third, and fifth lens units are fixed, and the second and fourth lens units move, with specific configurations of positive and negative lenses to disperse power and correct aberrations, including astigmatism and chromatic aberrations, facilitating high-speed autofocus.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the focus lens unit is made lightweight for high-speed autofocus, then autofocus speed is improved, but aberration correction capability deteriorates
Solution Approach 1:
The optical system divides the focusing function across multiple lens units (second and fourth lens units) rather than relying on a single heavy focus lens unit. This segmentation allows each unit to be lighter while collectively maintaining aberration correction capability through coordinated movement during focusing.
Solution Approach 2:
Different lens units are assigned specific functions: the second lens unit corrects astigmatism and other aberrations, while the fourth lens unit corrects chromatic aberrations. This local specialization of quality allows each lightweight unit to contribute to overall aberration correction without requiring any single unit to be overly complex or heavy.
2Adaptability or versatility
If the optical system is designed with wide angle of view and large aperture ratio, then imaging performance is improved, but aberration correction becomes more difficult
Solution Approach 1:
The patent assigns specific aberration correction functions to different lens units: the second lens unit with positive refractive power corrects astigmatism and other monochromatic aberrations, while the fourth lens unit corrects chromatic aberrations. This localized quality distribution enables effective aberration correction across the wide angle of view and large aperture ratio.
Solution Approach 2:
The optical system employs dynamic aberration correction through the coordinated movement of the second and fourth lens units during focusing. This dynamic adjustment maintains aberration correction performance across the entire focusing range from infinity to close-up shots, even with wide angle of view and large aperture ratio.
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 enables an optical system with a small size, wide angle of view, and large aperture ratio, effectively suppressing aberration fluctuations during focusing, thereby achieving high-speed autofocus.
Implementation Method 1
a second lens unit L2 having positive refractive power, a third lens unit L3, a fourth lens unit L4 having positive refractive power
Implementation Method 2
The third lens unit L3 includes at least one positive lens and one negative lens. The fourth lens unit L4 includes at least two positive lenses and one negative lens
Data Source
AI summary
An optical system includes a plurality of lens units. The lens units consisting of, in order from an object side to an image side, a first lens unit, a second lens unit having positive refractive power, a third lens unit, a fourth lens unit having positive refractive power, and a fifth lens unit. During focusing, the first lens unit, the third lens unit, and the fifth lens unit are fixed, and the second lens unit and the fourth lens unit move. The second lens unit consists of one lens component. The third lens unit includes at least one positive lens and one negative lens. The fourth lens unit includes at least two positive lenses and one negative lens.