Imaging Lens Layout for Compact Closeup Aberration Control

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Solution Overview

Problem

Existing imaging lenses struggle to maintain high optical performance while achieving a small size, particularly in closeup imaging scenarios.

Innovation Solution

The imaging lens is configured with a first lens group having positive refractive power and a second lens group with negative refractive power, where only the second lens group moves during focusing, and satisfies specific conditional expressions to optimize refractive power distributions and lens arrangements, including the use of cemented lenses and aspherical surfaces to correct aberrations and reduce size.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If the lens structure is simplified to reduce size, then the imaging lens can achieve a compact form factor, but optical performance deteriorates due to insufficient aberration correction

Engineering Contradiction:

Improvelens sizeVSAvoidoptical performance

Core Design Contradiction:

Volume of moving objectVSReliability

Solution Approach 1:

The imaging lens is divided into multiple lens groups (first lens group with positive refractive power, second lens group with negative refractive power, and optionally third lens group with positive refractive power). Each group contains specifically designed lenses (including cemented lenses combining positive and negative lenses) that work together to correct different types of aberrations while maintaining a compact overall structure.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the lens system have specialized functions: the first lens group handles primary focusing, the second lens group corrects chromatic and spherical aberrations through its negative refractive power and cemented lens configuration, and the third lens group (when present) fine-tunes optical performance. This local optimization allows compact size without sacrificing overall optical quality.

Inventive Principle:

Principle #3Local quality

2Adaptability or versatility

If the lens structure is simplified to achieve closeup imaging capability, then the lens can focus on close objects, but aberration correction becomes insufficient

Engineering Contradiction:

Improvecloseup imaging capabilityVSAvoidaberration correction

Core Design Contradiction:

Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The second lens group is designed to move along the optical axis during focusing, enabling the lens to adjust its configuration for different object distances including closeup imaging. This dynamic adjustment maintains optimal aberration correction across various focusing conditions while keeping the lens structure relatively simple.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

Cemented lenses are employed within the lens groups, combining positive and negative lenses with different refractive indices and Abbe numbers. This composite approach allows simultaneous correction of chromatic aberration (through dispersive properties) and spherical aberration (through refractive power balancing), achieving high manufacturing precision in aberration correction.

Inventive Principle:

Principle #40Composite materials

3Reliability

If more lens elements are added to improve optical performance, then aberration correction is enhanced, but the lens size increases

Engineering Contradiction:

Improveoptical performanceVSAvoidlens size

Core Design Contradiction:

ReliabilityVSVolume of moving object

Solution Approach 1:

Multiple lens functions are merged into compact configurations: cemented lenses combine positive and negative elements in close proximity to achieve both chromatic and spherical aberration correction simultaneously. The lens groups are arranged to perform multiple functions (focusing, aberration correction, field curvature control) within a minimized spatial envelope, avoiding the need for numerous separate elements.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent employs lenses with specifically selected refractive indices and Abbe numbers to maximize aberration correction efficiency. By optimizing these optical parameters, the design achieves high optical performance with fewer elements, as each lens contributes maximally to correcting multiple aberration types simultaneously.

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

This configuration enables high optical performance with a compact form factor, effectively correcting various aberrations and maintaining imaging quality during closeup imaging.

Implementation Method 1

a first lens group G1 having a positive refractive power; and a second lens group G2 having a negative refractive power

Methodology Applied

Scientific EffectRefraction: Refraction

Data Source

PatentUS12474551B2Imaging lens and imaging apparatus

Publication Date: 2025.11.18 FUJIFILM CORP

AI summary

The imaging lens includes, successively in order from a position closest to an object side, a first lens group that has a positive refractive power and a second lens group that has a negative refractive power. During focusing, only the second lens group moves. The first lens group consists of a first A group, an aperture stop, and a first B group, in order from the object side. The second lens group includes at least one positive lens. The imaging lens satisfies predetermined conditional expressions.