Three-Group Optical System for Wide-Angle Aberration Correction

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Solution Overview

Problem

Existing fixed focal point optical systems with a positive lens group on the image side face challenges in correcting various aberrations when increased in diameter.

Innovation Solution

An optical system comprising a first lens group with positive refractive power, a second lens group with positive refractive power, and a third lens group with negative refractive power, where the second lens group moves along the optical axis, satisfying specific conditional expressions to correct aberrations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If the optical system is increased in diameter, then the field of view and light gathering capability are improved, but the ability to correct various aberrations deteriorates

Engineering Contradiction:

Improveoptical system diameterVSAvoidaberration correction

Core Design Contradiction:

Area of stationary objectVSManufacturing precision

Solution Approach 1:

The optical system is divided into three distinct lens groups with specific refractive power configurations (positive, positive, negative). This segmentation allows each group to contribute differently to aberration correction, enabling the system to maintain good aberration correction performance even when the overall diameter is increased.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Each lens group is assigned specific local optical properties (refractive powers and magnification characteristics) that are optimized for their particular function. The second lens group is designed with specific magnification ratios to correct coma aberration, while the third lens group corrects other aberrations, allowing localized optimization throughout the system.

Inventive Principle:

Principle #3Local quality

2Device complexity

If a fixed focal point optical system with a positive lens group on the image side is used, then the structure is simplified, but the aberration correction capability deteriorates when the diameter is increased

Engineering Contradiction:

Improveoptical system structureVSAvoidaberration correction

Core Design Contradiction:

Device complexityVSManufacturing precision

Solution Approach 1:

The system divides the optical components into three functional lens groups rather than using a single positive lens group structure. This segmentation maintains relative structural simplicity while enabling superior aberration correction through the coordinated action of the three groups with different refractive powers.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention changes the fundamental parameter configuration from a single positive lens group to a combination of three lens groups with alternating positive and negative refractive powers. This parameter change fundamentally improves the aberration correction capability while maintaining a relatively simple overall structure.

Inventive Principle:

Principle #35Parameter changes

3Adaptability or versatility

If the second lens group moves along the optical axis for focusing, then the focusing capability from infinity to short distances is improved, but the system complexity increases

Engineering Contradiction:

Improvefocusing rangeVSAvoidlens group movement mechanism

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The system introduces dynamic focusing capability by allowing the second lens group to move along the optical axis. This dynamic element enables the system to adjust its focal length and maintain focus from infinity to short distances, transforming a static system into an adaptable one.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

Only the second lens group is designed to move for focusing, while the first and third lens groups remain stationary. This localized movement approach provides the necessary focusing adaptability while minimizing the overall system complexity and mechanical requirements.

Inventive Principle:

Principle #3Local quality

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 favorable optical performance throughout the focusing range from infinity to short distances, effectively correcting coma aberration, astigmatism, and other aberrations, maintaining a compact design and wide angle of view.

Implementation Method 1

an optical system includes a first lens group having positive refractive power, a second lens group having positive refractive power, and a third lens group having negative refractive power

Methodology Applied

Scientific EffectRefraction: Refraction

Data Source

PatentUS12455430B2Optical system, optical apparatus, and method of manufacturing optical system

Publication Date: 2025.10.28 NIKON CORP

AI summary

An optical system comprises a first lens group having positive refractive power, a second lens group having positive refractive power, and a third lens group having negative refractive power, arranged in order from an object side. When focusing, the second lens group moves along an optical axis. The optical system satisfies the following conditional expression0.30<{1−(β2)2}×(β3)2<2.00where β2 is a lateral magnification of the second lens group for a state of focusing on infinity, andβ3 is a lateral magnification of the third lens group.