Zoom Optical Layout for Aberration-Stable Lens Grouping
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Solution Overview
Problem
Existing zoom optical systems struggle to effectively correct aberrations such as spherical aberration, coma aberration, and curvature of field during zooming, particularly in photographic and video cameras, due to inadequate refractive power distribution among lens groups.
Innovation Solution
A zoom optical system comprising a first lens group with positive refractive power, a second lens group with negative refractive power, a third lens group with positive refractive power, and a succeeding lens group, where the first lens group is fixed relative to the image surface, and the third lens group moves towards the image surface during zooming, adhering to specific focal length ratios defined by conditional expressions to optimize refractive powers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the refractive power distribution among lens groups is not optimized, then the aberration correction is insufficient, but increasing the refractive power of lens groups may cause spherical aberration and coma aberration
Solution Approach 1:
The patent applies parameter changes by precisely controlling the refractive powers of individual lens groups through conditional expressions. Specifically, it defines the relationship between the refractive power of the third lens group (P3) and the succeeding lens group (PE) as -8.00 < P3/PE < -0.30, and between the first lens group (P1) and succeeding lens group as 0.30 < P1/PE < 3.40. By adjusting these parameters within specified ranges, the system achieves optimal aberration correction while minimizing harmful aberrations.
Solution Approach 2:
The patent employs composite materials by combining multiple lens groups with different refractive powers and optical characteristics. The system integrates a first lens group with positive refractive power, a second lens group with negative refractive power, a third lens group with positive refractive power, and a succeeding lens group. This composite structure allows for balanced aberration correction across different zoom states while controlling spherical and coma aberrations through the synergistic interaction of various lens elements.
2Manufacturing precision
If the lens groups are arranged to correct aberrations effectively, then the imaging quality improves, but the drive mechanism becomes more complex
Solution Approach 1:
The patent applies segmentation by dividing the optical system into distinct lens groups with specific functions. The first lens group (G1) has positive refractive power and is fixed, the second lens group (G2) has negative refractive power, the third lens group (G3) has positive refractive power and moves during zooming, and the succeeding lens group (GR) includes a last lens group (GL) arranged nearest to the image surface. This segmented structure enables effective aberration correction while allowing for simplified drive mechanisms by assigning specific movement responsibilities to particular lens groups.
Solution Approach 2:
The patent implements dynamics by introducing movable lens groups that can adjust their positions during zooming operations. Specifically, the third lens group (G3) moves toward the image surface during zooming from wide angle to telephoto end, while the first lens group (G1) remains fixed. This dynamic arrangement allows the system to maintain optimal aberration correction across varying focal lengths without requiring all lens groups to be movable, thus balancing imaging quality with drive mechanism complexity.
3Manufacturing precision
If the focal length ratio between lens groups is not controlled, then the aberration correction is inadequate, but strict control of focal length ratios increases manufacturing difficulty
Solution Approach 1:
The patent applies parameter changes by establishing specific conditional expressions for focal length ratios between lens groups. The system defines -8.00 < P3/PE < -0.30 for the ratio between the third lens group and succeeding lens group, and 0.30 < P1/PE < 3.40 for the ratio between the first lens group and succeeding lens group. These parameter ranges provide clear manufacturing guidelines that balance aberration correction requirements with manufacturability, avoiding overly strict constraints while ensuring adequate performance.
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 excellent correction of spherical aberration, coma aberration, and curvature of field across various zoom states, enabling high-quality imaging with reduced aberration fluctuations and simplified drive mechanisms.
Implementation Method 1
a first lens group G1 having a positive refractive power, a second lens group G2 having a negative refractive power, a third lens group G3 having a positive refractive power
Data Source
AI summary
A zoom optical system comprises a first lens group having a positive refractive power, a second lens group having a negative refractive power, a third lens group having a positive refractive power, and a succeeding lens group, which are arranged in order from an object side. During zooming, distances between adjacent lens groups change, and the first lens group is fixed with respect to an image surface. During zooming from a wide angle end state to a telephoto end state, the third lens group moves toward an image surface. The succeeding lens group includes a last lens group arranged to be nearest to the image surface. Further, the following conditional expression is satisfied.-10.00<f3/(-fE)<3.50,where f3 represents a focal length of the third lens group, andfE represents a focal length of the last lens group.