Zoom Lens System Aberration Correction via Cemented Groups
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Solution Overview
Problem
Existing zoom lenses struggle to achieve a compact design with high optical performance and a high zoom ratio while maintaining a wide angle and large aperture, which is challenging due to the difficulty in correcting various aberrations such as curvature of field and distortion.
Innovation Solution
A zoom lens system comprising multiple lens groups with specific configurations, including cemented lenses, that move along the optical axis to adjust focal lengths, ensuring a high zoom ratio and optical performance by satisfying conditional expressions that optimize lens barrel length and aberration correction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If a zoom lens system is designed to be compact with wide angle and large aperture, then the lens barrel length is reduced and aperture is increased, but it becomes difficult to correct various aberrations such as curvature of field and distortion
Solution Approach 1:
The zoom lens system is divided into four distinct lens groups (G1, G2, G3, G4) with alternating negative and positive refractive powers. Each group contains specific lens elements with defined shapes and positions. This segmentation allows independent optimization of each group's function while maintaining overall compactness and aberration correction capability throughout the zoom range.
Solution Approach 2:
Specific lens elements are designed with particular shapes to address local aberration issues. For example, the fourth lens element in G1 has a convex surface facing the object side with specific curvature characteristics to correct distortion, while the fifth lens element has a concave surface facing the object side to control curvature of field. These localized shape optimizations enable effective aberration correction within the compact structure.
2Length of stationary object
If a zoom lens system achieves high zoom ratio with compact design, then the lens barrel length is reduced, but the optical performance and aberration correction become difficult to maintain
Solution Approach 1:
The zoom lens system employs dynamic movement of lens groups along the optical axis to achieve zooming. The first lens group G1 moves to change focal length, while the second lens group G2 moves to maintain the image plane position. This dynamic configuration allows the system to maintain high optical performance across the entire zoom range from wide angle to telephoto within a compact form factor.
Solution Approach 2:
The system utilizes specific parameter relationships to maintain optical performance. Conditional expressions define optimal ranges for focal lengths, distances between lens groups, and curvature radii. By maintaining these parameters within specified ranges, the system achieves high zoom ratio while preserving aberration correction and optical quality throughout the zoom range.
3Reliability
If the first lens group includes multiple negative meniscus lens elements with specific configurations, then aberration correction is improved, but the device complexity increases
Solution Approach 1:
The third lens element and fourth lens element are cemented together to form a single cemented lens unit. This merging reduces the number of air-glass interfaces, simplifies the overall structure, and improves aberration correction by combining the optical functions of both elements in a unified configuration. The cemented lens design maintains compactness while effectively controlling chromatic and monochromatic aberrations.
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 zoom lens system achieves a compact design with high optical performance and a high zoom ratio, effectively correcting aberrations and maintaining image quality across the wide angle and telephoto ends, making it suitable for applications in digital cameras and network cameras.
Implementation Method 1
a first lens element having a negative meniscus shape with a concave surface of the shape facing the image side, a second lens element having a negative meniscus shape with a concave surface of the shape facing the image side, a third lens element with a concave surface of the element facing the image side, a fourth lens element with a convex surface of the element facing the object side, and a fifth lens element with a concave surface of the element facing the object side
Data Source
AI summary
A zoom lens system includes, in the following order from an object side toward an image side, a first lens group with negative power, a second lens group with positive power, a third lens group with negative power, and a fourth lens group with positive power. The first lens group includes, in the following order from the object side toward the image side, a first lens element having a negative meniscus shape with a concave surface facing the image side, a second lens element having a negative meniscus shape with a concave surface facing the image side, a third lens element with a concave surface facing the image side, a fourth lens element with a convex surface facing the object side, and a fifth lens element with a concave surface facing the object side. The third lens element and the fourth lens element compose a cemented lens.