Zoom Lens Aberration Correction via Perpendicular Lens Group Movement

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Solution Overview

Problem

Conventional zoom lenses face challenges in maintaining optical performance and correcting image blurring due to camera shake, especially at longer focal lengths, where aberrations and decentering errors increase, leading to reduced image quality.

Innovation Solution

A zoom lens configuration with a specific arrangement of lens groups, including a first positive lens group, a second negative lens group with sub-groups having positive and negative refractive powers, and a rear group, where the second lens group is movable perpendicular to the optical axis to correct blurring, and the distances between lens groups change during zooming to maintain optical performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Length of stationary object

If a positive-lead zoom lens with extended telephoto focal length is used, then the focal length range is improved, but aberrations and decentering errors increase leading to reduced optical performance

Engineering Contradiction:

Improvefocal lengthVSAvoidoptical performance

Core Design Contradiction:

Length of stationary objectVSManufacturing precision

Solution Approach 1:

The zoom lens is divided into multiple lens groups (first positive lens group, second negative lens group with sub-groups, and rear group) with specific internal structures. The second lens group is further segmented into sub-groups and lens components that can move independently perpendicular to the optical axis, allowing separate correction of aberrations while maintaining the extended focal length capability.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The second lens group is designed to be movable perpendicular to the optical axis during correction of image blurring. This dynamic adjustment allows the lens to compensate for camera shake and correct decentering errors that occur at longer focal lengths, thereby maintaining optical performance across the extended focal length range.

Inventive Principle:

Principle #15Dynamics

2Length of stationary object

If the focal length is extended to the telephoto end, then the zoom range is improved, but image blurring due to camera shake increases

Engineering Contradiction:

Improvefocal lengthVSAvoidimage blurring

Core Design Contradiction:

Length of stationary objectVSObject-affected harmful factors

Solution Approach 1:

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The lens system incorporates a mechanism to detect image blurring caused by camera shake and actively corrects it by moving the second lens group perpendicular to the optical axis. This feedback-based correction system counteracts the increased susceptibility to blurring at telephoto focal lengths.

Inventive Principle:

Principle #23Feedback

3Object-affected harmful factors

If a vibration-isolating lens is added to correct image blurring, then the correction capability is improved, but the device complexity increases

Engineering Contradiction:

Improveimage blurring correctionVSAvoidlens structure

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The second lens group, which is already part of the zoom mechanism, is given dual functionality: it participates in the zooming operation and simultaneously serves as the vibration-isolating element that corrects image blurring. This multi-functionality avoids adding separate vibration correction mechanisms, thereby limiting the increase in device complexity.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The vibration isolation function is merged with the existing second lens group of the zoom lens system. By combining the zooming function and vibration correction function into a single lens group structure, the patent avoids the need for separate vibration correction mechanisms, thus limiting the increase in device complexity.

Inventive Principle:

Principle #5Merging (Combining)

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 effectively corrects various aberrations, including spherical and coma aberrations, while reducing decentered aberrations, thereby maintaining high optical performance and preventing image blurring across the entire zoom range.

Implementation Method 1

a first lens group having positive refractive power; a second lens group having negative refractive power

Methodology Applied

Scientific EffectRefraction: Refraction

Implementation Method 2

A part of the second lens group is movable in a direction perpendicular to an optical axis during correction of image blurring

Methodology Applied

Scientific EffectDecentering correction:

Data Source

PatentUS11953662B2Zoom lens, lens barrel, and image-capturing device

Publication Date: 2024.04.09 RICOH CO LTD

AI summary

A zoom lens includes a first lens group having positive refractive power, a second lens group having negative refractive power, and a rear group. The second lens group consists of a second sub-first lens group having positive or negative power, and a second sub-second lens group having negative power. The second sub-second lens group consists of, sequentially from the object side toward the image: a positive second-first lens component; a negative second-second lens component; and a negative second-third lens component. During zooming from a short focal length end to a long focal length end, a distance between the first lens group and the second lens group increases, and a distance between the second lens group and the rear group decreases. A part of the second lens group is movable in a direction perpendicular to an optical axis during correction of image blurring.