Variable Magnification Lens System with Orthogonal Vibration Reduction

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Solution Overview

Problem

There is a growing demand for a variable magnification optical system with a wide angle of view and satisfactory optical performance, which existing systems have not adequately addressed due to challenges in achieving both a wide angle of view and effective image stabilization.

Innovation Solution

A variable magnification optical system comprising a first lens group with negative refractive power, a second lens group with positive refractive power, a third lens group with negative refractive power, and a fourth lens group with positive refractive power, where the third lens group includes a movable 32nd lens group for vibration reduction and a 31st lens group with adjustable position, satisfying specific focal length ratios to correct image blur and aberrations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of moving object

If a wide angle of view is implemented in a variable magnification optical system, then the field of view is improved, but optical performance deteriorates due to difficulty in achieving effective image stabilization

Engineering Contradiction:

Improvefield of viewVSAvoidoptical performance

Core Design Contradiction:

Area of moving objectVSReliability

Solution Approach 1:

The third lens group is divided into two sub-groups: a vibration-reduction lens group (32nd lens group) that moves orthogonally to the optical axis for image stabilization, and another lens group (31st lens group) that remains fixed during vibration reduction. This segmentation allows the system to maintain wide-angle capability while implementing effective image stabilization through selective movement of the 32nd lens group.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The vibration-reduction lens group (32nd lens group) is configured to be movable in a direction orthogonal to the optical axis, enabling dynamic adjustment to correct image blur caused by camera shake. This dynamic capability allows the system to adapt to varying vibration conditions while maintaining wide-angle optical performance.

Inventive Principle:

Principle #15Dynamics

2Area of moving object

If the F-value decreases and image height increases to achieve wider angle of view, then the field of view is improved, but aberration correction becomes more difficult

Engineering Contradiction:

Improvefield of viewVSAvoidaberration correction

Core Design Contradiction:

Area of moving objectVSManufacturing precision

Solution Approach 1:

The 32nd lens group is specifically designed with negative refractive power and configured for orthogonal movement to address local aberration issues in the wide-angle configuration. This localized optimization allows the system to maintain acceptable aberration correction performance even with decreased F-value and increased image height.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent specifies that the 32nd lens group must have negative refractive power and satisfy specific conditional expressions regarding focal length ratios. These parameter constraints ensure that aberration correction remains effective despite the challenges posed by wide-angle design with decreased F-value and increased image height.

Inventive Principle:

Principle #35Parameter changes

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 a wide angle of view while effectively correcting image blur and aberrations, maintaining satisfactory optical performance across various focal lengths and image stabilization, even when the F-value decreases and image height increases.

Implementation Method 1

a 32nd lens group (G32) configured to be movable so as to have a component in a direction orthogonal to an optical axis in order to correct image blur

Methodology Applied

Scientific EffectVibration reduction:

Implementation Method 2

the system performing varying magnification by changing the distance between the first lens group and the second lens group, the distance between the second lens group and the third lens group, and the distance between the third lens group and the fourth lens group

Methodology Applied

Scientific EffectMagnification variation:

Implementation Method 3

a first lens group (G1) having a negative refractive power; a second lens group (G2) having a positive refractive power; a third lens group (G3) having a negative refractive power; and a fourth lens group (G4) having a positive refractive power

Methodology Applied

Scientific EffectRefraction: Refraction

Data Source

PatentUS11415787B2Variable magnification optical system, optical apparatus, and method for manufacturing variable magnification optical system

Publication Date: 2022.08.16 NIKON CORP

AI summary

A variable magnification optical system includes, in order from an object: a first lens group (G1) having a negative refractive power; a second lens group (G2) having a positive refractive power; a third lens group (G3) having a negative refractive power; and a fourth lens group (G4) having a positive refractive power. The system performs varying magnification by changing the distance between the first lens group and the second lens group, the distance between the second lens group and the third lens group, and the distance between the third lens group and the fourth lens group. The third lens group includes a 32nd lens group (G32) configured to be movable so as to have a component in a direction orthogonal to an optical axis in order to correct image blur as a vibration-reduction lens group (VR) and a 31st lens group (G31) disposed at an object-side of the 32nd lens group. The 32nd lens group has negative refractive power, and the system satisfies Conditional Expression (1) below.0.200<f1/f3<0.900 (1)