Zoom Lens Rear Subunit Aberration Correction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing zoom lens systems face challenges in achieving a high zoom ratio with excellent aberration correction over the entire zoom range, particularly at wide and telephoto ends, while maintaining a large aperture ratio and wide field angle, due to difficulties in setting refractive powers and lens structures to reduce chromatic aberration, spherical aberration, and other optical errors.
Innovation Solution
A zoom lens system comprising a first stationary lens unit with positive refractive power, a second moving lens unit with negative refractive power, a third moving lens unit for image plane variation correction, and a fourth lens unit with a front and rear subunit separated by a maximum air interval, where the rear subunit includes two negative and at least three positive lenses, with specific Abbe number conditions met to optimize material dispersion and partial dispersion ratios.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a lens unit for changing focal length range is removably inserted between lens subunits in the fourth lens unit, then the focal length range can be extended, but it becomes difficult to maintain high optical performance and correct various aberrations
Solution Approach 1:
The fourth lens unit is divided into front and rear subunits with a large air interval between them, allowing the rear subunit to be optimally configured for aberration correction while the front subunit handles focal length adjustment. This segmentation enables the system to maintain high optical performance across different focal length ranges.
Solution Approach 2:
The rear subunit of the fourth lens unit is specifically designed with a particular lens configuration (including positive and negative lenses with specific Abbe numbers) to locally optimize aberration correction in the region where the extender lens interfaces, ensuring high optical performance regardless of the extender lens configuration.
2Productivity
If the lens structure of the fourth lens unit is not suitably set, then achieving a high zoom ratio becomes difficult, but various aberrations such as chromatic aberration, spherical aberration, and coma cannot be reduced
Solution Approach 1:
The patent specifies precise parameter ranges for the lenses in the rear subunit of the fourth lens unit, including Abbe numbers (ν1p, ν2p, ν1n, ν2n) and focal length ratios. By optimizing these parameters, the system achieves both high zoom ratio and excellent aberration correction simultaneously.
Solution Approach 2:
The rear subunit employs a composite lens structure with multiple positive and negative lenses made from materials with different Abbe numbers. This composite approach allows simultaneous correction of multiple types of aberrations while maintaining high zoom capability.
3Reliability
If a large aperture ratio, high magnification-varying ratio, and wide field angle are achieved, then the refractive powers and lens structures must be precisely set, but this increases system complexity
Solution Approach 1:
The fourth lens unit is segmented into front and rear subunits with a large air interval, allowing independent optimization of each subunit. The rear subunit focuses on aberration correction with a specific multi-element structure, while the front subunit handles magnification variation, simplifying the overall design process.
Solution Approach 2:
The rear subunit of the fourth lens unit is designed to perform multiple functions simultaneously: correcting chromatic aberration, spherical aberration, coma, and other off-axis aberrations. This multi-functional design achieves high optical performance without proportionally increasing complexity.
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 excellent correction of lateral and axial chromatic aberrations across the entire zoom range, achieving high optical performance with a wide angle, high magnification, and large aperture, effectively addressing the limitations of previous systems.
Implementation Method 1
a fourth lens unit which does not move for zooming, and in which: the fourth lens unit includes a front subunit and a rear subunit... the rear subunit 4B includes two negative lenses and at least three positive lenses
Data Source
AI summary
A zoom lens system having a high zoom ratio and excellently correcting various aberrations over an entire zoom range between a wide angle end and a telephoto end to obtain high optical performance in the entire zoom range, includes, in order from an object side to an image side, a first lens unit having a positive refractive power, a second lens unit having a negative refractive power, a third lens unit, and a fourth lens unit. The fourth lens unit includes a front subunit and a rear subunit, the rear subunit being constituted by two negative lenses and at least three positive lenses. The rear subunit includes a first rear-subunit and a second rear-subunit. Each of the first rear-subunit and the second rear-subunit includes a negative lens and at least one positive lens. Lens materials are suitably set for the first rear-subunit and the rear second-subunit.