Variable Magnification Optical System Aberration Correction

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Solution Overview

Problem

Existing variable magnification optical systems face challenges in correcting curvature of field and spherical aberration in telephoto and wide-angle states, with limitations in focal length ratios affecting optical performance and system compactness.

Innovation Solution

A variable magnification optical system comprising specific lens groups with varying refractive powers and focal lengths, where air distances between neighboring lens groups are adjusted to satisfy conditional expressions, allowing for optimal correction of aberrations and maintaining a compact design.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If the focal length ratio between the first and sixth lens groups is not optimized, then the optical system can be simpler to design, but the curvature of field and spherical aberration cannot be effectively corrected

Engineering Contradiction:

Improvecorrection of curvature of field and spherical aberrationVSAvoidfocal length ratio constraints

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent applies parameter changes by establishing specific constraints on the focal length ratio between the first lens group (fA) and sixth lens group (fB), expressed as 0.30 < -fA/fB < 0.60. This parameter optimization enables effective correction of curvature of field and spherical aberration across the variable magnification range while maintaining a manageable design complexity.

Inventive Principle:

Principle #35Parameter changes

2Manufacturing precision

If more lens groups are added to improve aberration correction, then optical performance improves, but the system becomes less compact

Engineering Contradiction:

Improveoptical performance and aberration correctionVSAvoidsystem compactness

Core Design Contradiction:

Manufacturing precisionVSVolume of moving object

Solution Approach 1:

The patent employs six lens groups that serve multiple functions simultaneously: they provide variable magnification capability, correct various aberrations including curvature of field and spherical aberration, and maintain a compact overall structure. Each lens group contributes to both imaging quality and system compactness through optimized focal lengths and air distance variations.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent utilizes dynamic adjustment of air distances between neighboring lens groups during magnification variation. This dynamic configuration allows the system to maintain optimal aberration correction across different focal lengths while keeping the physical size compact, as the lens groups move relative to each other to achieve both goals.

Inventive Principle:

Principle #15Dynamics

3Adaptability or versatility

If air distances between lens groups are fixed, then the structure is simpler, but magnification variation and aberration correction are limited

Engineering Contradiction:

Improvemagnification variation and aberration correctionVSAvoidair distance adjustment mechanism

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent implements dynamic air distance adjustment between neighboring lens groups to enable magnification variation from wide-angle to telephoto ends. This dynamic configuration, combined with the specific focal length ratio constraint, allows the system to correct curvature of field and spherical aberration effectively across the full magnification range while maintaining a relatively simple adjustment mechanism.

Inventive Principle:

Principle #15Dynamics

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 superb optical performance by effectively correcting curvature of field and spherical aberration across different focal lengths, ensuring a compact and lightweight design while maintaining excellent imaging quality.

Implementation Method 1

a first lens group having negative refractive power; a second lens group having positive refractive power; a third lens group having negative refractive power; a fourth lens group having positive refractive power; a fifth lens group having negative refractive power; and a sixth lens group having positive refractive power; upon varying magnification, air distances between the neighboring lens groups being varied

Methodology Applied

Scientific EffectRefraction: Refraction

Data Source

PatentUS10690896B2Variable magnification optical system, optical device, and production method for variable magnification optical system

Publication Date: 2020.06.23 NIKON CORP

AI summary

Comprising, in order from an object side: a first lens group G1 having negative refractive power; a second lens group G2 having positive refractive power; a third lens group G3 having negative refractive power; a fourth lens group G4 having positive refractive power; a fifth lens group G5 having negative refractive power; and a sixth lens group G6 having positive refractive power;upon varying magnification, air distances between the neighboring lens groups G1-G6 being varied; anda predetermined conditional expression being satisfied, thereby providing a variable magnification optical system which has excellent optical performance, an optical apparatus, and a method for manufacturing a variable magnification optical system.