Zoom Lens Compactification via Nested Group Arrangement
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Solution Overview
Problem
Conventional zoom lenses face challenges in achieving both miniaturization and high performance, particularly in small-sized devices like cellular phones and digital still cameras, where they need to provide high image quality with minimal image deterioration and reduced thickness for enhanced portability.
Innovation Solution
A zoom lens configuration with a first lens group having negative refractive power and a light path changing member, a second lens group composed of two lenses with negative refractive power, a third lens group with a stop and lenses having positive and negative refractive power, and a fourth lens group with variable refractive power, where the first and fourth lens groups are fixed, and the second and third lens groups move to adjust magnification, satisfying specific conditional expressions for optimal performance and size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the zoom lens includes multiple lens groups that can move to change magnification, then the magnification range is extended, but the overall length and thickness of the lens increases
Solution Approach 1:
The patent implements nesting by placing the second lens group (negative refractive power) inside the first lens group (positive refractive power) at the telephoto end, and arranging lens groups in a compact nested configuration throughout the zoom range. This allows multiple lens groups to occupy overlapping or adjacent spaces rather than requiring sequential linear arrangement, significantly reducing the overall length while maintaining the ability to change magnification.
Solution Approach 2:
The patent transitions from a conventional linear arrangement of lens groups along the optical axis to a two-dimensional arrangement where lens groups are positioned at different radial distances and angular positions. The second lens group is arranged concentrically with respect to the optical axis, and lens groups are positioned at different heights, utilizing spatial dimensions beyond just the optical axis length to achieve compactification.
2Reliability
If more lenses are added to correct aberrations and improve image quality, then the performance is improved, but the device complexity and number of components increases
Solution Approach 1:
The patent applies local quality by assigning specific refractive power characteristics to specific lens groups based on their functional requirements. The first lens group has positive refractive power for overall focusing, the second lens group has negative refractive power specifically for correcting chromatic aberration and distortion, and the third lens group has variable refractive power for fine-tuning. This targeted approach achieves high image quality with fewer lenses by optimizing each lens group's specific properties rather than adding more lenses uniformly.
Solution Approach 2:
The patent uses composite optical design by combining lens groups with different refractive power characteristics and materials in a specific arrangement. The first lens group (positive), second lens group (negative), and third lens group (variable) work together as a composite optical system where each group contributes specific aberration correction capabilities, achieving high performance through material and design composition rather than simply increasing the total number of lenses.
3Length of stationary object
If the lens groups are arranged to minimize thickness for portability, then the device is more portable, but the space for moving lens groups is reduced
Solution Approach 1:
The patent implements dynamics by enabling the second lens group to move relative to the first lens group along the optical axis during zooming operations. The second lens group can shift position to adjust the focal plane and correct aberrations at different magnification levels. This dynamic adjustment capability is achieved within the compact thickness by utilizing the available space efficiently and allowing controlled movement rather than fixed positioning, maintaining portability while preserving full functionality.
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 allows for a small-sized zoom lens with high image quality and effective aberration correction across the entire magnification range, maintaining image quality from point-blank range to infinity while minimizing lens thickness and weight.
Implementation Method 1
a light path changing member that changes a traveling direction of an incident light beam
Implementation Method 2
a first lens group that has a lens having negative refractive power
Data Source
AI summary
A zoom lens includes a first lens group that has a lens having negative refractive power and a light path changing member; a second lens group that includes a lens having positive refractive power and a lens having negative refractive power, and has negative refractive power as a whole; a third lens group that includes a stop, a front group lens having positive refractive power, and a rear group lens having negative refractive power, and has positive refractive power as a whole; and a fourth lens group having positive or negative refractive power. Upon changing magnification from a wide-angle end to a telephoto end, the first lens group and the fourth lens group are fixed. The second lens group moves to the object side after the second lens group moves to an image side, and the third lens group linearly moves to the object side.